Clinical Acupuncture

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	Gabriel Stux
	Richard Hammerschlag
	(Editors)
  Clinical 
 Acupuncture

Scientific Basis

	With Contributions by
	B. M. Berman, S. Birch, C. M. Cassidy, Z. H. Cho, J. Ezzo, R. Hammerschlag, J. S. Han, L. Lao, T. Oleson, B. Pomeranz, C. Shang, G. Stux, C. Takeshige
	With 40 Illustrations, some in Color and 27 Tables
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    Preface

	In 1988, when "Scientific Bases of Acupuncture" was published, its editors noted that 12 years had passed since the acupuncture endorphin hypothesis was first postulated, an event that marked the start of serious basic research on acupuncture. The editors also suggested that more was known about the mechanisms of acupuncture analgesia than many procedures of conventional medicine and, in consequence, it was time to stop referring to acupuncture as an "experimental procedure."
	Now another 12 years have passed. Acupuncture research, both basic and clinical, has greatly expanded. Modern biomedical techniques, including those of molecular biology and medical imaging, have revealed increasingly detailed physiological correlates of acupuncture action. Clinical researchers from Europe, North America, and Asia have devised a variety of protocols to test acupuncture efficacy according to generally accepted standards for randomized controlled trials. A critical review of acupuncture research by the United States Food and Drug Administration resulted in the label "experimental" being legally removed from the packaging of acupuncture needles in 1996, just as the editors of "Scientific Bases of Acupuncture" had proposed. A year later, again in large part a result of increased and improved acupuncture research, a consensus conference on acupuncture convened by the U. S. National Institutes of Health concluded its panel report with the endorsement "... there is sufficient evidence of acupuncture's value to expand its use into conventional medicine and to encourage further studies of its physiology and clinical value" (JAMA 280:1518-24).
	The present book is nothing less than a celebration of the coming of age of acupuncture research. Reflecting the broad spectrum of modernday acupuncture research, its chapters include an assessment of systematic reviews of acupuncture trials, proposed standards of acupuncture treatment in clinical research, qualitative methods to gauge patient satisfaction with Oriental medicine treatment, and physiological models of auricular acupuncture, meridians, and homeostatic responses to acupuncture. Our hope is that the state-of-the-art reviews presented in these pages will encourage consideration of the millennia-old practice of acupuncture as a contemporary, evidence-based treatment option.
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    Contents

	I Acupuncture Analgesia - Basic Research ................... 1 
	B. Pomeranz
	2 Mechanisms of Acupuncture Analgesia Produced by Low Frequency Electrical Stimulation of Acupuncture Points .. 29 
	C. Takeshige
	3 Opioid and Antiopioid Peptides: A Model of Yin-Yang Balance in Acupuncture Mechanisms of Pain Modulation ............ 51 
	J.-S. Han
	4 The Past, Present, and Future of Meridian System Research ... 69 
	C. Shang
	5 Functional Magnetic Resonance Imaging of the Brain in the Investigation of Acupuncture ........................ 83  
	Z.-H. Cho, C.-S. Na, E. K. Wang, S.-H. Lee, and 1.-K. Hong
	6 Neurophysiological Basis of Auricular Acupuncture .......... 97 
	T. Oleson
	7 Assessing Clinical Efficacy of Acupuncture: What Has Been Learned from Systematic Reviews of Acupuncture? ........... 113 
	J. Ezzo, L. Lao and B. M. Berman
	8 An Overview of Acupuncture in the Treatment of Stroke, Addiction, and Other Health Problems ..................... 131 
	S. Birch
	9 Beyond Numbers: Qualitative Research Methods for Oriental Medicine .................................... 151 
	C. M. Cassidy
	10 Proposed Standards of Acupuncture Treatment for Clinical Studies ...................................... 171 
	G. Stux and S. Birch
	11 Assessing Clinical Efficacy of Acupuncture: Considerations for Designing Future Acupuncture Trials ................... 187  
	L. Lao, J. Ezzo, B. M. Berman, and R. Hammerschlag
	12 Future Directions for Research on the Physiology of Acupuncture ......................................... 211 
	R. Hammerschlag and L. Lao
	Subject Index .............................................. 221 
    Contributors

	Brian M. Berman (bberman@compmed.ummc.umaryland.edu)
	Complementary Medicine Program, University of Maryland School of Medicine, James L. Kernan Hospital Mansion, 2200 Kernan Drive, Baltimore, MD 21207-6697, USA
	Stephen Birch (71524.3461@compuserve.com)
	Foundation for the Study of Traditional East Asian Medicine W.G. Plein 330, 1054 SG Amsterdam, The Netherlands
	Claire M. Cassidy (honeeum@aol.com)
	Paradigms Found Consulting, 6201 Winnebago Road, Bethesda, MD 20816, USA
	Zang Hee Cho (zcho@uci.edu)
	Department of Radiological Sciences, University of California, Irvine, CA 92697, USA
	Jeanette Ezzo (jeanetteezzo@prodigy.net)
	Epidemiology Faculty, Project LEAD, 1905 W. Rogers Avenue, Baltimore, MD 21209, USA
	Richard Hammerschlag (rzhammer@compuserve.com)
	Oregon College of Oriental Medicine, 10525 S.E. Cherry Blossom Drive, Portland, OR 97216, USA
	Ji-Sheng Han (jshh@public.bta.net.cn)
	Neuroscience Research Center, Beijing Medical University, Beijing, China 100083
	1.-K. Hong
	Dept. of Information Engineering, Kwangju Institute of Science and Technology, Kwanju, Korea
	Lixing Lao (LLao@compmed.ummc.umaryland.edu)
	Complementary Medicine Program, University of Maryland School of Medicine, James L. Kernan Hospital Mansion, 2200 Kernan Drive, Baltimore, MD 21207-6697, USA
	S.-H. Lee
	Dept. of Acupuncture, South Baylo University, Anaheim, CA 92801, USA
	C.-S. Na
	Dept. of Meridianology, Oriental Medical College, Dong Shin University, Naju, Korea
	Terry Oleson (terryoleson@earthlink.net)
	Health Care Alternatives, PMB 2657, 8033 Sunset Boulevard, Los Angeles, CA 90046-2427, USA
	Bruce Porneranz (varadi9180@home.com)
	Departments of Zoology and Physiology, University of Toronto, 25 Harbor Street, Toronto, Ontario M5S lAl, Canada
	Charles Shang (cshang@emory.edu)
	Department of Medicine, Emory University School of Medicine, 69 Butler Street, S.E., Atlanta, GA 30303, USA
	Gabriel Stux (106657.3550@compuserve.com)
	Acupuncture Center Dusseldorf, Goltsteinstraf3e 26, 40211 Dusseldorf, Germany
	Chifuyu Takeshige (Makoton@cc.showa-u.ac.jp)
	Department of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142, Japan
	E. K. Wang (ekwong@uci.edu)
	Dept. of Ophthalmology, University of California, Irvine, CA 92697, USA
  CHAPTER I

  Acupuncture Analgesia - Basic Research

B. Pomeranz

1.1

Introduction

	In recent years, acupuncture analgesia (AA) in the west has been restricted mainly to the treatment of chronic pain and not used for surgical procedures, except for demonstration purposes. In some Western countries, however, AA is used in combination with nitrous oxide, sufficient N2O being given to render the patient unconscious but not for analgesia [80], or with fentanyl [89]. How could a needle inserted in the hand possibly relieve a toothache? Because such phenomena do not conform to accepted physiological concepts, scientists were puzzled and skeptical. Many explained it by the well-known placebo effect, which works through suggestion, distraction, or even hypnosis [201, 2021. In 1945, Beecher [9] showed that morphine relieved pain in 70 % of patients, while sugar injections (placebo) reduced pain in 35% of patients who believed they were receiving morphine. Thus, many medical scientists in the early 1970s assumed that AA worked by this placebo (psychological) effect. However, there were several problems with this idea. How does one explain the use of AA in veterinary medicine over the past 1000 years in China and approximately 100 years in Europe and its growing use on animals in America? Animals are not suggestible and only a very few species are capable of the still reaction (so-called animal hypnosis). Similarly, small children also respond to AA. Moreover, several studies in which patients were given psychological tests for suggestibility did not show a good correlation between AA and suggestibility [101]. Hypnosis has also been ruled out as an explanation, as two studies [6, 58] have shown that hypnosis and AA respond to naloxone differently, AA being blocked and hypnosis being unaffected by this endorphin antagonist.
	Until 1973, the evidence for AA was mainly anecdotal, with a huge collection of case histories drawn from one quarter of the world's population. Unfortunately, there were few scientifically controlled experiments to convince the skeptics. In the past 25 years, however, this situation has changed considerably. Scientists have been asking two important questions: does AA really work by a physiological rather than a placebo/psychological effect and, if so, by what mechanism?
	The first question had to be approached via controlled experiments to rule out placebo effects, spontaneous remissions, etc. These experiments have been carried out in clinical practice on patients with chronic pain, in the laboratory on humans, studying acute laboratory-induced pain (see Sect. 1.6), and on animals (see Sect. 1.6). From these numerous studies, it can be concluded that AA works much better than placebo. Hence, AA must have some physiological basis. But what are the possible mechanisms? Only the answer to the second question (how does AA work?) could possibly dispel the deep skepticism toward acupuncture.
1.2

Neural Mechanisms of Acupuncture Analgesia

	Twenty years of research in my laboratory coupled with over 100 papers from the western scientific literature led to a compelling hypothesis: AA is initiated by the stimulation of small diameter nerves in muscles which send impulses to the spinal cord. Then, three neural centers (spinal cord, midbrain, and pituitary) are activated to release transmitter chemicals (endorphins and monoamines) which block "pain" messages. Figures I and 2 summarize various aspects of the hypothesis of the neural mechanism of AA.
	We explain the figures and present some of the evidence for this hypothesis. Fig. 1 shows how pain messages are transmitted from the skin to the cerebral cortex. On the left is skin, with a muscle beneath it in the lower left corner. An acupuncture needle penetrates the muscle. The next rectangle is the spinal cord, and to the right are rectangles depicting various brain structures: midbrain, thalamus, pituitary-hypothalamus, and cerebral cortex. As shown in the legend to Fig. 1, open triangles represent excitatory terminals (acting at the synapse) and closed triangles inhibitory terminals. Large arrows indicate the direction of impulse flow in the axons and small arrows the painful stimulus.
  	Fig. 1. Pain transmission
 	To understand the pain transmission as shown in Fig. 1, follow the thick arrows at the top. An injury to the skin activates the sensory receptors of small afferent nerve fibers (labeled 1) of A delta and C axon size. (Nerve fibers are classified by size and according to whether they originate in skin or muscle: large diameter myelinated nerves A beta (skin) or type I (muscle) carry "touch" and proprioception, respectively. Small diameter myelinated A delta (skin) or types II and III (muscle) carry "pain" messages, as do the smallest unmyelinated C (skin) and type IV (muscle). Types II, III, IV, and C also carry nonpainful messages.) Cell 1 synapses onto the spinothalamic tract (STT) cell in the spinal cord (labeled 2). The STT (cell 2) projects its axon to the thalamus to synapse onto cell 3, which sends impulses to the cortex to activate cell 4 (probably in the primary somatosensory cortex). I must point out that this diagram is oversimplified, since there are at least six possible pathways carrying pain messages from the spinal cord to the cortex but, for the sake of clarity, only the STT is shown.
	It is best to go to Fig. 2 to see how the other cells operate (cells 5-14). In Fig. 2, the acupuncture needle is shown activating a sensory receptor (square) inside the muscle, and this sends impulses to the spinal cord via the cell labeled 5, which represents type II and III muscle afferent nerves (small diameter myelinated afferents). Type II afferents are thought to signal the numbness of De Qi needling sensations and type III the fullness (heaviness and mild aching) sensation [203]. Any soreness felt is carried by unmyelinated type IV afferents from the muscle, although soreness is not usually part of the De Qi sensations. In some acupuncture points, e. g., at the fingertips or over major nerve trunks, there are no muscles and here different fibers are involved. If cutaneous nerves are activated, A delta fibers are the relevant ones. Cell number 5 synapses in the spinal cord onto an anterolateral tract (ALT) cell (labeled 6) which projects to three centers, the spinal cord, the midbrain, and the pituitaryhypothalamic complex.
  	Fig.2. Acupuncture (low frequency, high intensity)
 	Within the spinal cord, cell 6 sends a short segmental branch to cell 7, which is an endorphinergic cell. This cell releases either enkephalin or dynorphin, but not betaendorphin. (There are three families of endorphins: enkephalin, [i-endorphin, and dynorphin, and in Fig. 2 these are all labeled E.) The spinal cord endorphins cause presynaptic inhibition of cell 1, preventing transmission of the painful message from cell 1 to cell 2.
	As there are very few axo-axonal synapses between cell 7 and cell 1, it is thought that the endorphin peptides merely diffuse to the receptors located on the terminals of cell 1. There are also postsynaptic endorphin synapses acting directly on cell 2 from cell 7, although these are not shown. Thus, enkephalins and dynorphins block pain transmission at the spinal cord level. The presynaptic inhibition probably works by reducing calcium current inflow during the action potential in the terminals of cell 1, resulting in reduced release of the pain transmitter.
	What Fig. 2 does not show are the numerous peptides present in the cell I terminals, including cholecystokinin, somatostatin, neurotensin, bombesin, calcitonin gene-related peptide, angiotensin, substance P, and vasoactive intestinal peptide. So far, only cholecystokinin (CCK) has been shown to play a role in AA [72], acting like the opiate antagonist naloxone to block endorphin-mediated AA. Perhaps the ratio of CCK and endorphins is the important variable in producing analgesia.
	As shown in Fig. 2, cell 6 also projects to the midbrain, ascending the spinal cord in the ALT. Here, it excites cells 8 and 9 in the periaqueductal gray (PAG), which release enkephalin to disinhibit cell 10, which is thus excited) and in turn activates the raphe nucleus, located in the caudal end of the medulla oblongata (cell II), causing it to send impulses down the dorsolateral tract (DLT) to release monoamines (serotonin and norepinephrine, labeled M) onto the spinal cord cells (66]. Cell 2 is inhibited by postsynaptic inhibition, while cell 1 is presynaptically inhibited via cell 7. (Cell 7 is excited while cell 2 is inhibited by the monoamines.) Either of the two monoamine mechanisms can suppress the pain transmission. In addition to the raphe magnus, which releases serotonin onto the cord, there is the adjacent reticularis paragigantocellularis (not shown), which may release norepinephrine via the DLT onto the spinal cord. Norepinephrine binds to an alpha receptor in the cord to block pain transmission.
	Some believe that serotonin and norepinephrine act synergistically in this regard [64]. There is some evidence that the peptide neurotensin may be the excitatory transmitter between cells 10 and 11 [7]. The precise relationship of these descending monoamine effects to AA is not clear at present, and results suggest that some of the raphe serotonin effect in AA may be mediated by ascending fibers from the raphe to the forebrain (not shown). More work is needed on the role of the monoamine system in AA.
	Even less well understood is the action of cell 6 onto cells 12 and 13, the pituitary hypothalamic complex. Cell 12 in the arcuate nucleus may activate the raphe via ]3-endorphin, and cell 13 in the hypothalamus may release [i-endorphin from the pituitary gland from cell 14 (Fig. 2). While there is some agreement that AA is accompanied by elevated beta-endorphin in the CSF [ 169] and blood and that pituitary lesions suppress AA [42], there is no agreement on how the (3-endorphin from the pituitary reaches the brain to cause analgesia. Too little of it reaches the blood to cross the blood-brain barrier in sufficient quantities. Some evidence suggests that the pituitary-portal venous system can carry hormones in a retrograde direction directly to the brain [13]. Perhaps cell 14 can influence cell 9, as shown by the thin arrows in Fig. 2, without having to cross the blood-brain barrier. If so, the role of circulating endorphins in the blood is unclear. However, there is an important correlate of pituitary 13-endorphin release: adrenocorticotrophic hormone (ACTH) and ]3-endorphin are coreleased into the circulation on an equimolar basis [19, 158]. (They stem from a common precursor).
	The ACTH travels to the adrenal cortex, where cortisol is released into the blood [43], which may explain why acupuncture is helpful in blocking the inflammation of arthritis and the bronchospasms of asthma (the doses of cortisol released by acupuncture are small and finely regulated, thus avoiding the side effects of cortisol drug therapy). Because of insufficient data, other centers implicated in the AA-endorphin effects have been left out of our description. These include the nucleus accumbens, amygdala, habenula, and anterior caudate [77, 2241. In Fig. 2, the axon from the STT cell (cell 2) has a collateral fiber dropping down to excite cell 8 in the midbrain to cause analgesia. This is because of a phenomenon discovered in 1979 by Le Bars et al. [95] called DNIC (diffuse noxious inhibitory control), in which one pain inhibits another. Its role in AA has been suggested but never clearly established [ 14].
	In summary, acupuncture stimulates nerve fibers in the muscle which send impulses to the spinal cord and activate three centers (spinal cord, midbrain, and hypothalamus/pituitary) to cause analgesia. The spinal site uses enkephalin and dynorphin to block incoming messages with stimulation at low frequency and other transmitters (perhaps gamma-aminobutyric acid, or GABA) with stimulation at high frequency. The midbrain uses enkephalin to activate the raphe descending system, which inhibits spinal cord pain transmission by a synergistic effect of the monoamines, serotonin, and norepinephrine. The midbrain also has a circuit which bypasses the endorphinergic links at high frequency stimulation. Finally, at the third, or hypothalamus/pituitary center, the pituitary releases (3-endorphin into the blood and CSF to cause analgesia at a distance. Also, the hypothalamus sends long axons to the midbrain and activates the descending analgesia system via [3-endorphin. This third center is not activated at high frequency stimulation but only at low frequency.
	What is the practical significance of this three-level system? When needles are placed close to the site of pain or in the tender (trigger, or Ah Shi) points, they are maximizing the segmental circuits operating at cell 7 within the spinal cord while also bringing in cells 11 and 14 in the other two centers (Fig. 2). When needles are placed in distal points far from the painful region, they activate the midbrain and hypothalamus-pituitary (cells 11 and 14) without the benefit of local segmental effects at cell 7. Moreover, cells 11 and 14 produce analgesia throughout the body, while cell 7 produces analgesia only locally.
	Local segmental needling usually gives a more intensive analgesia than distal nonsegmental needling because it uses all three centers. Generally, the two kinds of needling (local and distal) are used together on each patient to enhance one another. Another important practical consequence of this system is the frequency/intensity effect. As shown in Fig. 2, low frequency (2-4 Hz), high intensity needling works through the endorphin system and acts in all three centers, while high frequency (50-200 Hz), low intensity needling only activates cells 7 and 11, bypassing the endorphin system. Numerous studies have shown that the types of analgesia produced by these two approaches are quite different [2]: the low frequency method produces an analgesia of slower onset and, more importantly, of long duration, outlasting the 20minute stimulation session by 30 minutes to many hours. Also, its effects are cumulative, improving increasingly after several treatments. In contrast, the high frequency, low intensity analgesia is rapid in onset but of very short duration and with no cumulative effects. Many authors have arbitrarily described the low frequency, high intensity type of analgesia as "acupuncture-like" transcutaneous electrical nerve stimulation (TENS) and the high frequency, low intensity type as "conventional" TENS.
	Because low frequency, high intensity analgesia produces a cumulative effect, repeated treatment produces more and more benefit for the patient [109, 154, 2001 or laboratory animal 11511. This could be due to long-lasting effects of endorphins in the low frequency system. Most conventional TENS (high frequency) devices must be worn continuously by the patients, as the effect is of short duration, and in over 70 % of cases the effectiveness wears off after some months of continuous use because tolerance develops 12091. In contrast, low frequency acupuncture need only be given daily or twice a week because of its long-term cumulative effects [ 1541. Indeed, too frequent application of low frequency acupuncture produces tolerance. For example, if applied continuously for 6 h, the analgesia weakens and finally disappears 1711. This effect is cross-tolerant with morphine tolerance [711, and the mechanisms involved may be similar to those of addiction to endorphins. Hence, spacing the acupuncture treatments with long enough intervals may prevent tolerance while promoting the cumulative effects.
	Perhaps the failure of some Western clinics to achieve success is due to the use of very infrequent treatments (e.g., one per week) and the termination of treatment after only five to ten sessions. In some clinics in Asia, patients are treated daily for a month, then weekly for 6 months, and the results reported anecdotally are excellent. Of course, some patients will never respond to acupuncture for various reasons; nonresponders may be genetically deficient in opiate receptors. We have shown that mice genetically lacking endorphin receptors respond poorly to acupuncture [ 135]. Other failures may be due to deficiency in endorphin molecules; rats lacking endorphin compounds respond poorly to acupuncture [123]. Some nonresponders can be converted to responders by treatment with the safe drug jd-phenylalanine, which potentiates endorphins [39, 51, 183]. In clinical practice, a strategy must be developed to allow nonresponders to be recognized while not aborting therapy too soon for potential responders who might show delayed cumulative effects. (One way is to decide after five treatments: if there is no benefit whatsoever, abort; if mild to moderate effects occur, continue and reassess after 10-15 treatments.) Often, the cost of repeated office visits is prohibitive. Hence, our group developed a home acupuncturelike TENS device which gives De Qi sensations and can be used by the patient over acupuncture points for 30 min/day for several months 1411.
	Most books might have ended the discussion of AA right here. However, because acupuncture is relatively new to Western medicine and so controversial, more data are needed to convince students that the acupuncture mechanisms outlined in Figs. 1 and 2 are well-established. Those who are in a hurry can skim or skip the next few pages but should nonetheless scrutinize the reference list (this omits the huge literature from China which, if included, would double the number of citations). It should be apparent that we know more about AA than about many chemical drugs in routine use. For example, we know very little about the mechanisms of most anesthetic gases but still use them regularly. The reader is also referred to the reviews [3, 66, 68, 76, 86, 100, 117, 139, 142, 143, 150, 168, 173, 215, 223, 226].
1.3

Evidence for Endorphins and Acupuncture Analgesia

	Perhaps the most exciting experiments which opened up the field of AA to scientific research were those in which endorphin antagonists (e.g., naloxone and naltrexone) were used. That naloxone could antagonize AA was reported initially by two groups [ 113, 147]. Studying acute laboratory-induced tooth pain in human volunteers, Mayer et al. [ 1 131 produced AA by manual twirling of needles in LI.4 (first dorsal interosseous muscle of the hand). In a double-blind design, they gave one group of subjects IV naloxone while another group received IV saline. The saline group achieved AA with a time course typical for clinical reports (30 min to onset of analgesia and effects lasting for over 1 h). The naloxone group showed no AA. As no controls received naloxone alone, one might argue that naloxone hyperalgesia simply subtracted from the analgesia of AA. However, this is probably not the case, since numerous studies on acute laboratory-induced pain have shown that naloxone alone rarely produces hyperalgesia [57]. This suggests that endorphins do not have a basal tone during acute pain. Mayer et al. [113] studied a control group receiving placebo injections. The placebo subjects were told to expect a strong analgesic effect and none was observed, as predicted from Beecher's work on acute pain, where only 3 % of subjects reported placebo analgesia [9].
	The other early naloxone study was by Pomeranz and Chiu [ 147] in awake mice; they used the mouse squeak latency paradigm and gave electroacupuncture (EA) at L1.4. Numerous control groups were used in this latter experiment in an attempt to determine some of the possible artifacts. Each group received one of the following treatments: EA alone, EA plus saline, EA plus IV naloxone, sham EA in a nonacupuncture point, naloxone alone, saline alone, and no treatment at all (just handling, restraint, and repeated pain testing). The results were unequivocal: naloxone completely blocked AA, sham EA produced no effect, and naloxone alone produced very little hyperalgesia (not enough to explain reduction of AA by subtraction). Moreover, the results in mice and in humans indicated firstly that AA was not a psychological effect and secondly that AA truly was blocked by naloxone. In a later study, Cheng and Pomeranz [36, 37] produced a dose-response curve for naloxone and found that increasing doses produced increasing blockade. In a third study in anesthetized cats [ 146] recording from layer-5 cells in the spinal cord (cell 2 in Fig. 1), the same researchers completely prevented the EA effects with IV naloxone.
	Since these early papers, there have been numerous studies in which systemically administered endorphin antagonists have been used to test the endorphin-AA hypothesis. Although most researchers reported naloxone antagonism [25, 28, 32, 34-39, 46, 53, 62, 78, 93, 97, 98, 133, 135, 146, 147, 151, 160, 164, 165, 170, 171, 174, 175, 187, 193, 208, 210, 224, 2251, some found no effects of naloxone [ 1, 30, 31, 137, 185, 200, 2111. Three of these seven failures were obtained with high frequency, low intensity stimulation, which is probably not endorphinergic [ 1, 200, 2111. In one of the failures 1311 low intensity stimulation was used which did not lead to De Qi sensations. In spite of this, four of seven subjects in that study showed naloxone antagonism.
	While the reasons for the other three negative papers [30, 137, 1851 are not entirely clear, a possible explanation has emerged. Antagonists work best when given before the treatment [ 144, 206] and fail to reverse analgesia that has already been initiated. Thus, naloxone can prevent AA but often cannot reverse it. (In the three failed experiments, researchers tried to reverse AA, giving the endorphin antagonist after, not before the acupuncture treatments.) Taken together, the overwhelming weight of evidence shows that naloxone antagonizes AA and that the few negative results may be due to poor timing of the naloxone administration. In biology, negative results are often less valid than positive ones.
	A few weeks after the first naloxone results were announced in the research news section of Science [ 110], a letter to the editor in the same journal justifiably criticized the use of naloxone as the sole proof of the AA-endorphin hypothesis 1751. This criticism is based mainly on the argument that naloxone might possess unknown side effects unrelated to opiate receptor blocking. Small doses which were effective in preventing AA in man (5. 10' M) and in mice and cats (10 " M) would tend to implicate receptor effects, but the effectiveness of small doses of naloxone is clearly not enough evidence to prove specificity 1162 1. However, since that letter was written, 17 different lines of experimentation have emerged which have independently provided support for the AA-endorphin hypothesis:
	1. Many different opiate antagonists block AA [33-37].
	2. Naloxone has a stereospecific effect [36, 371.
	3. Microinjection of naloxone or antibodies to endorphins blocks AA only if given into analgesic sites in the central nervous system [ 15, 45, 67, 72, 73, 133, 144, 151, 216, 221, 2241.
	4. Mice genetically deficient in opiate receptors show poor AA [135, 159].
	5. Rats deficient in endorphin show poor AA [123, 175 ).
	6. Endorphin levels rise in blood and CSF during AA and fall in specific brain regions during AA [5, 45, 52, 74, 77, 83, 90, 108, 111, 125, 136, 169, 195, 225].
	7. AA is enhanced by protecting endorphins from enzyme degradation [39, 45, 51, 54, 63, 82, 91, 123, 175, 2251.
	8. AA can be transmitted to a second animal by CSF transfer or by cross-circulation and this effect is blocked by naloxone [98, 105, 157].
	9. Reduction of pituitary endorphins suppresses AA [42, lll, 152, 177, 179, 180, 1811.
	10. There was a rise in messenger RNA for proenkephalin in brain and pituitary. This lasted 24-48 h after 30 min of EA, indicating a prolonged increased rate of enkephalin synthesis. This could explain the enduring effects of EA and the potentiation of repeated daily treatments [60, 220].
	11. There is cross-tolerance between AA and morphine analgesia, implicating endorphins in AA [33, 34, 711.
	12. AA is more effective against emotional aspects of pain. This is typical of endorphins [218].
	13. Lesions of the arcuate nucleus of the hypothalamus (the site of [3-endorphins) abolishes AA; this is cell 12 in Fig.2 [177, 178, 204].
	14. Lesions of the periaqueductal gray (site of endorphins) abolishes AA [205].
	15. The level of c-Fos gene protein (which measures increased neural activity) is elevated in endorphin-related areas of the brain during AA [59, 96, 132].
	16. Evidence suggests that, in addition to monoamines mediating 100 Hz EA effects, dynorphin (one of the three endorphins) may also be involved. Thus, at 100 Hz there is an elevation of dynorphin levels in the dorsal horn of rat spinal cord [217] and there is an elevation of dynorphin A in lumbar punctures in humans receiving 100 Hz EA [69, 70]. Moreover, rats given EA at 100 Hz show AA, which is blocked by the dynorphin kappa antagonist (norbinaltorphimine), while the EA at 2 Hz is blocked by mu and delta antagonists, suggesting involvement of enkephalins and [i-endorphin at these lower frequencies [34, 35].
	17. Electroacupuncture in rats elevated precursors of the three endorphins, preproenkephalin, preprodynorphin, and preproendorphin mRNA. Moreover, antisense nucleotides for c-fos or c-jun successfully blocked the EA-induced preprodynorphin mRNA [60].
	In summary, 17 different lines of research strongly support the AA-endorphin hypothesis. Despite so much convergent evidence for this hypothesis, skepticism persists:
	1. Some cite the few failures of naloxone to reverse AA [31]. It has already been suggested above that naloxone reversal experiments are prone to difficulty because naloxone prevents but does not reverse AA. Moreover, the number of successful naloxone antagonisms of AA far exceeds the number of failures (28 successes versus 7 failures). In general, negative results in biomedical research are less reliable than positive results.
	2. Some state that naloxone antagonism is necessary but not sufficient evidence [75]. That is why we have presented 17 different lines of evidence (only one line of evidence depends on naloxone).
	3. Some attack the animal studies of AA as being unrelated to AA in humans [31]. Firstly, there have been numerous experiments in humans with the same AAendorphin outcome as in lower animals. Secondly, the similarity of results across many species proves the generality of the phenomenon. Thirdly, there is no proper objective measure of pain in man. Fourthly, if skeptics are correct, then the entire animal "pain" literature should be discarded, a literature which provided our initial insights into endorphins, brain stimulation analgesia, TENS, and other results that have been highly applicable to human pain.
	4. Some are concerned that AA in animals may be merely stress-induced analgesia (which also releases endorphins) and hence has nothing to do with acupuncture in humans [311. At a conference on stress-induced analgesia at the New York Academy of Sciences, we gave a lecture entitled "Relation of stress-induced analgesia to acupuncture analgesia." Some of the points made in that paper [ 1401 were:
	A. Sham EA on nearby nonacupuncture points in animals induces no AA, thus controlling for stress [27, 43, 55, 56, 102, 147, 176, 186].
	B. AA elicited in anesthetized rats and cats or decerebrate cats does not involve psychological stress [27, 55, 56, 134, 144, 146, 148, 151, 152, 186].
	C. AA at one frequency is endorphin-mediated while, at another, it is serotoninmediated. Yet both give similar levels of stress [38, 1701.
	D. Many mechanisms of stress analgesia are very different from those of AA.
	E. Results in mice and rats were obtained with mild stimulation activating A beta nerve fibers, a nonpainful procedure no more stressful than sham point stimulation [133, 149, 186].
	In conclusion, the objections raised by a few skeptics are easily refuted. The overwhelming evidence supports the AA-endorphin hypothesis. Zhang [223] reviewed other differences between AA and stress analgesia:
	1. AA is reversible with naloxone but stress analgesia is only partly antagonized by large doses of naloxone (20 times higher than that for reversing AA).
	2. Plasma cyclic adenosine monophosphate (cAMP) levels decrease during AA but rise during stress analgesia.
	3. The periaqueductal gray is essential for AA but not for stress analgesia.
	4. Dorsolateral spinal cord lesions eliminate AA but not stress analgesia.
	Nevertheless, a note of caution is needed here. Some animal models of AA are indeed stressful to the animals, especially those done in the awake conscious state using strong stimulation of the needles. One such experiment involves the rat model used by Professor Han of Beijing Medical University which has been challenged by Professor Mayer of the University of Virginia [20-22].
1.4

Evidence for Midbrain Monoamines and Acupuncture Analgesia

	There are numerous papers implicating the midbrain monoamines in AA, especially serotonin and norepinephrine. As the raphe magnus in the brainstem contains most of the serotonin cells in the brain, lesions which destroy these cells or their axons in the DLT would presumably impair AA if serotonin were involved. Such lesions also abolish morphine analgesia, which is mediated by descending inhibition via the raphe-DLT-serotonin system [7]. Numerous experiments show that lesions to this system in animals block AA 140, 48, 87, 116, 163, 212]. Moreover, antagonistic drugs which block serotonin receptors also block AA in mice 140, 165]. In the above tests of the serotonin-AA hypothesis, the drugs were given systemically (usually IP). However, local microinjection studies produced surprising results, suggesting that the descending serotonin-1)LT inhibitory system may not be as important as the raphe projections to the forebrain: intrathecal injections of serotonin antagonists over the spinal cord produced no blockade of AA in rats 11331, while lesions of the ascending raphe tracts caused a selective decrease in cerebral serotonin and a correlated decrease in AA in the rat [65].
	Microinjection of serotonin antagonists into the various brain regions confirmed the importance of ascending serotonin pathways; AA was blocked by injections into the limbic system and the midbrain PAG [65]. Enhancement of AA was observed in mice [40] and rats [65] when serotonin was increased by giving 5-H'I'P (a precursor of 5-HT) systemically or intracerebroventricularly [65, 219], the latter route being more effective than the intrathecal route. Measurement of 5-HT and its metabolite 5- hydroxyindoleacetic acid (5-HIAA) in the brain and spinal cord of rats during AA showed increased synthesis and utilization of 5-HT [ 190, 222]. The importance of serotonin in AA has also been confirmed clinically in patients using the serotonin uptake blocker clornipramine, where AA was potentiated in a double-blind study 12211.
	All this leaves us with the questions of why a lesion of the DLT in the spinal cord inhibits AA [163] if spinal cord serotonin does not mediate AA effects and whether the DLT contains other transmitters that mediate AA. Mayer and Watkins suggest that a synergism between descending serotonin and norepinephrine is the possible answer 1112]. Indeed, Hammond [64] showed that combined intrathecal antagonists (for serotonin and norepinephrine) produced the best antagonism of descending analgesia produced by brainstem stimulation. Perhaps this should be tried for AA, since combined intrathecal antagonists should block AA more effectively than single antagonists.
	There have been studies on the effects of norepinephrine (alone, without serotonin) on AA. Intrathecal injection of a norepinephrine antagonist blocked AA, showing the importance of descending norepinephrine pathways [66]. Clearly, the monoamine story needs more work. If synergism of descending serotonin and norepinephrine is important, then combined intrathecal blockers should be used in all future studies of monoamines in AA. The relative roles of the ascending and descending tracts need to be clarified.
	In conclusion, there is no doubt that the monoamines (serotonin and norepinephrine) play a role in AA. Serotonin projections from the raphe to higher centers may mediate AA. Descending projections to the spinal cord via the DLT may work synergically with descending norepinephrine effects to block pain transmission in the spinal cord.
1.5

Evidence for Pituitary Hypothalamic System and Acupuncture Analgesia

	The third possible center mediating low frequency endorphin analgesia is the pituitary-hypothalamic system. The arcuate nucleus of the ventromedial hypothalamus and the pituitary gland contain all the ]i-endorphin cells in the brain [ 16]. As the arcuate cells have long axons, [i-endorphin is found in other brain loci, but it all originates from the hypothalamic cells [207]. The arcuate cells can produce analgesia via these long axons (stimulating the midbrain PAG, for example). Lesions of the arcuate nucleus abolish AA in rats [ 1611.
	There is a good deal of confusion regarding the possible relationship of the pituitary (hormonal) [3-endorphins to pain modulation. We have already mentioned the evidence (lesion and blood biochemistry studies) implicating pituitary endorphins in AA. Involvement of the pituitary in other forms of analgesia has also been studied. For example, stress-produced analgesia is at least partly mediated by pituitary [3endorphins [ 158]. Here problems arise, because pituitary ablation is a very unreliable technique. Moreover, injection of the drug naloxone could have side effects. To make matters worse, in some species (e.g., rat) the blood-brain barrier for [3-endorphin is very tight [158], although mice, rabbits, and man have a weaker barrier [192]. A new route for pituitary endorphins to reach the brain while bypassing the barrier has been discovered [13, 121] in the hypothalamic pituitary portal system (reverse flow occurs). Perhaps the endorphins can reach the third ventricles and, via the CSF, influence such structures as the PAG. Perhaps more important than the pituitary release of endorphins is the corelease of adrenocorticotropic hormone (ACTH) which occurs during AA 1108, 111, 1251, because this stimulates the adrenals to raise blood cortisol levels after AA 118, 43, 99, 1021. Sham acupuncture does not raise blood cortisol levels 143, 99], thus ruling out stress as the cause of cortisol release. It is tempting to speculate that this cortisol mediates the treatment effects of acupuncture in arthritis, effects which seem to go beyond analgesia [411. Similarly, asthma might be helped by cortisol release 112, 182, 184].
Conclusions

	In conclusion, the evidence for the mediation of AA by endorphins is very strong, while that for the involvement of monoamines needs more work to verify the possible synergism of serotonin and norepinephrine. Moreover, the circuits depicted in Figs. 1 and 2 are quite well established, although there is some uncertainty about the role of the pituitary.
1.6

Acupuncture Points - Do They Really Exist?

	The question of the existence of acupuncture points, or acupoints, has been explored in several ways:
	1. By comparing the effects of needling at true points versus sham points
	2. By studying the unique anatomical structures at acupoints
	3. By studying the electrical properties of skin at acupoints
	4. By studying the nerves being activated by acupuncture at acupoints
1.6.1

Does Needling Work Better at True Points Than at Sham Points?

	Several experimenters have shown that, for acute laboratory-induced pain in human subjects, needling of true points produces marked analgesia while needling of sham points produces very weak effects [23, 29, 172]. These results were clear-cut, because effects of sham point stimulation are nonexistent in acute laboratory pain. Placebo pills also have poor efficacy in acute pain, causing analgesia in only 3 %% of cases.
	In contrast to those clear-cut results, the work on chronic pain patients has been less convincing. Placebo analgesia in chronic pain has a strong effect, working in 30%-35% of patients. Moreover, needling in sham points seems to work in about 33 %-50 % of patients, while true points are effective in about 55 %-85 % of cases (197]. Therefore, to show statistical significance in the differences between sham point needling and true point needling requires huge numbers of patients (at least 122 per study); and experiments that would allow definitive conclusions have not yet been done [ 1971. It is puzzling that sham acupuncture works in 33 %-50 % of patients with chronic pain but not at all in acute laboratory-induced pain. Because of these problems, the specificity of acupoints in humans has been shown only in acute pain studies but has yet to be properly studied in patients with chronic pain, where the number of patients studied has never exceeded the required statistical minimum of 122 [199].
	In animal studies in mouse [1471, cat [27, 56], horse [43], rat [176, 186], and rabbit [55, 102], many researchers have shown that true acupuncture works better than sham needling in acute pain studies. These results are consistent with the research on acute pain in humans. In such studies, it is important to use mild stimulation in awake animals to avoid inducing stress: strong stimulation of sham sites could cause stress-induced analgesia [140]. Stress analgesia is a well-documented phenomenon [ 107] that is often mediated by endorphins. If the stimulation used is very strong, animals are highly stressed by both true and sham point needling.
	Hence, numerous studies on acute pain in animals and humans clearly demonstrate that AA from needling true points is far superior to AA from needling sham points. However, more studies are needed to make the comparison in chronic pain.
1.6.2

Are There Unique Anatomical Structures at Acupuncture Points?

	Despite several histological studies of the skin and subcutaneous structures under acupoints, no unique structures have been found. However, several authors [61, 119, 120] have made the astute observation that the majority of acupuncture points coincide with trigger points. For example, Melzack et al. found that 71 % of acupuncture points do so [119, 120]. This suggests that needles activate the sensory nerves which arise in muscles. This agrees with findings that stimulation of muscle afferents is important for producing analgesia [44, 104, 203].
	The work of Travell on trigger points, begun in 1952 [188] and culminating in a large book published in 1983 [1891, shows that there are small hypersensitive loci in the myofascial structures which, when touched or probed, give rise to a larger area of pain in an adjacent or distant (referred) area. She observed that "dry needling" (with needles containing no drugs) of these trigger points produced pain relief. When sites are tender, the Chinese call them Ah Shi points, and needling of them is recommended. Trigger points can often be found outside muscle bellies, in skin, scars, tendons, joint capsules, ligaments, and periosteum [ 189]. Travell stresses the importance of precise needling of trigger points, as missing the tense knotted muscle fiber could aggravate the problem by causing spasms. Similarly, strong electrical stimulation should be avoided. Thus, mild stimulation with needles inserted directly into trigger points is recommended [189]. The majority of trigger points are located on or near the following acupoints: SI.10-13, 15; SJ.13, 14; UB.12-17, 28, 29, 36-41, 48, 49; and GB.27-30. Although the cause of trigger point tenderness is unknown, one possibility is that poor inactivation of calcium by muscle sarcoplasmic reticulum causes calcium to cross-link the actin and myosin, with ensuing permanent contracture. How needling rectifies this problem, however, is unclear [189].
	In a review on the subject of the anatomy of acupuncture points, Dung [50] listed ten structures which are found in the vicinity of acupoints (see especially numbers 5, 6, and 9 regarding trigger points). In decreasing order of importance, he found:
	1. Large peripheral nerves. The larger the nerve, the more effective.
	2. Nerves emerging from a deep to a more superficial location.
	3. Cutaneous nerves emerging from deep fascia.
	4. Nerves emerging from bone foramina.
	5. Motor points of neuromuscular attachments. A neuromuscular attachment is the site where a nerve enters the muscle mass. This is not always the actual neuromuscular synapse, which may lie a few centimeters further along the nerve, after it has divided into smaller branches. The pathophysiological significance of this neuromuscular attachment is unknown. Travell emphasizes that many authors have used the term "motor point" interchangeably with "trigger point," but in most cases these are not at the same locations [ 189].
	6. Blood vessels in the vicinity of neuromuscular attachments.
	7. Nerves composed of fibers of varying sizes (diameters). This is more likely on muscular nerves than on cutaneous nerves.
	8. Bifurcation points of peripheral nerves.
	9. Ligaments (muscle tendons, joint capsules, fascial sheets, collateral ligaments), as these are rich in nerve endings.
	10. Suture lines of the skull.
	It is obvious from this list that no particular structure dominates at acupuncture points. Perhaps the major correlate is the presence of nerves, be they in large nerve bundles (items 1-8) or nerve endings (items 9 and 10). A report by Heine revealed that 80 %%, of acupoints correlate with perforations in the superficial fascia of cadavers. Through these holes, a cutaneous nerve vessel bundle penetrates to the skin. If replicated, this finding could be the morphological basis for acupoints [79].
	The abolition of AA by injection of local anesthetics into an acupoint before stimulation begins [44, 149] strongly suggests that nerves are important for this phenomenon (Sect. 1.6.4). However, we should not rule out other mechanisms to explain the effects of acupuncture in immunological, allergic, and other non-AA phenomena. One can speculate on the possible release of arachidonic acid from lesioned membranes during needling, giving rise to leukotrienes and Prostaglandins, which could affect immunity. Also, currents of injury (electric currents generated from a hole in the skin) might be important for nerve regeneration (Sect. 1.6.3).
	It would be easy to find out if local anesthetics prevent all acupuncture effects as they do for AA, but few experiments have been done on nonanalgesic effects. Evidence suggests the existence of channels which may correlate with meridians. Vernejoul et al. [ 196] injected to a depth of 4 mm a radioactive isotope into 130 humans subcutaneously, using technetium-99 in sodium pertechnetate in a volume of 0.05 nil. They compared migration of the isotope (using a gamma camera) after injection into acupoints with injection into nonacupoints. They claimed that vertical lines of migration were seen only from acupoints. These extended as far as 30 cm within 5 min and resembled meridian lines in their distribution. Moreover the migration velocity was altered under pathological conditions. From the photographs in the papers, however, it was difficult to draw conclusions. Also, one must rule out lymphatic drainage. Several reports have favored venous drainage as the explanation for this isotope migration, raising serious doubts about this method for studying meridians [94, 167, 213, 215]. Replications by other laboratories are definitely needed before conclusions can be drawn from this controversial research.
1.6.3

Do Acupuncture Points Have Unique Physiological Features?

	There have been a number of reports that the skin resistance (impedance) over acupuncture points is lower than that of surrounding skin [8, 26], but this result has been attributed to pressure artifacts from electrodes [ 114, 127, 191 ]. Normally, dry skin has a DC resistance in the order of 200000-2 million ohms. At acupuncture points, this is down to 50000 ohms in the studies claiming unique properties of acupoints. These observations have led to the marketing of "point finders," pencil-shaped metal-tipped probes attached by wires to an ohmmeter. The circuit is completed by a second electrode in a hand-held metal cylinder (with large skin contact on the sweaty palm and hence with a low resistance in the order of 1000 ohms). The point finder generally measures DC resistance based on Ohm's law (E = IR): a constant voltage is applied to the wires and the resultant current (I) is measured, from which resistance (R) is instantly computed. This can be read out on a Wheatstone bridge or directly on a meter. Most devices produce a beeping tone whose frequency or intensity is proportional to the resistance being measured. This allows the clinician to move the roving pencil probe around the body surface while listening to the tones. Anecdotal reports suggest that these devices work best in certain regions (e.g., hands, face, or ears) in which acupuncture points and low resistance often coincide (but see [118] for negative results on the ear). It is further claimed that, during disease of particular organs, the resistances at acupoints are abnormally low, even lower than the usual low resistance at acupoints (but see [ 118]). Indeed, the Japanese (Ryodoraku) method of measuring the acupoint skin resistance on the body has been in widespread use in Japan since its introduction by Nakatani in 1950 [124], while Nogier and the French school [126] have made observations at ear acupoints (see also [1181). In Germany, the Voll machine has concentrated on another skin electrical phenomenon, whereby the initial peak resistance reading is ignored while the capacitative "fall-back" of the reading to a steady-state (higher resistance) value is considered diagnostic. In the USSR, Gai- kin developed the toboscope as a point finder, which was shown at the Montreal World Fair in 1967. This was further developed by Nechushkin in the 1970s.
	There have been two careful experiments performed to validate the claims of ear "point finders" [118, 129]. Oleson et al. [129] took 40 patients and, in a "blind" design, compared diagnoses made with a point finder (9V DC, 50 mA) on the ear with diagnoses made on the same patients by means of a Western medical workup. The researchers were blind to the Western diagnosis to ensure that no clues were available to them. Amazingly, the correlation between ear diagnosis and Western diagnosis was 72.5%, which was highly significant [1291. Melzack and Katz [118] could find no difference in conductance between acupuncture points and nearby control points in patients with chronic pain [ 118] when they measured skin resistance in the ear. Unfortunately, neither Ryodoraku nor the Voll machine has been validated by similar controlled studies. Moreover, further claims for the Voll machine that homeopathic remedies placed in parallel with the measuring wires can modify the readings and thereby indicate appropriate treatments for the diagnosed ailment have never been scientifically tested [88].
	Until recently, we were quite skeptical of the entire skin resistance phenomenon. This was because the measurements were not made in accordance with established biophysical practice. Neither the published reports [8, 26, 155, 156] nor clinical anecdotal observations were based on properly conducted studies, as pointed out by others 126, 114, 127, 1911. We improved the methodology. Ag/AgCI electrodes were used with a salt bridge to avoid electrochemical potentials, biphasic pulses were used to avoid polarization from DC currents, small (microampere) currents were applied to avoid electrical damage to skin, spring-loaded probes were used to avoid mechanical injury of the skin, and very small amounts of saline were supplied from the salt bridge through a Millipore filter to overcome skin moisture variations. When these precautions were taken, a highly reliable technique developed (1661. Preliminary results to date suggest that acupuncture points do sometimes have lower impedance than surrounding skin. Whether or not this is true, the point finders commercially available are very unreliable 11661.
	We have no idea what the physiological significance could be, if any, of low resistance at acupoints. It is known that sweating has a profound effect on skin resistance; this forms the basis of lie detector tests. Stress, which activates the sympathetics, causes sweating and a drop in skin resistance. In a preliminary study, we determined that sweating occurs uniformly over the skin surface, equally at acupoints and over the surrounding skin. Moreover, the earlobe is practically devoid of sweat glands, yet resistance phenomena are claimed to occur there as well [129] (but see [ 1181). We have not yet validated the claims of a drop in resistance during disease; if this phenomenon proves to be true, the pathophysiological mechanism is unclear. Can sympathetics affect local sweating during disease? Why should this be localized to acupoints when sweating normally appears to be diffusely organized? It is also unclear why, acupoints in normal people should have a low resistance. Could the presence of a large nerve, emerging from deep tissues to more superficial layers, induce skin changes?
	Another finding at acupuncture points is the presence of a voltage source [8] (i.e., a potential difference is reported to exist between acupoints and the neighboring skin), with the points being measured at 5 mV higher than the nonpoints. Unfortunately, as mentioned above for resistance, most of these voltage measurements did not use state of the art biophysical methodology. This is particularly unfortunate, as electrochemical potential artifacts produced at the electrode-skin interface are large compared with the millivolts being generated by the body. An outstanding study was published by Jaffe et al. [85], showing that the human skin has a resting potential across its epidermal layer of 20-90 mV (outside negative, inside positive). This paper paid no attention to acupuncture points. Nevertheless, one can speculate that acupuncture points, having low resistance, tend to short-circuit this battery across the skin and hence give rise to a source of current in a source-sink map of the skin. In other words, acupuncture points provide a path of least resistance for currents driven by the 20-90 mV resting potential which exists across the entire skin, which is consistent with the 5 mV readings mentioned above [8].
	An important measurement in the same paper by Jaffe et al. [85] showed that a lesion (a cut) in the skin produces a current of injury which is due to short-circuiting of the skin battery. Preliminary results [166] indicate that insertion of acupuncture needles into the skin might also produce a current of injury which has biological influences on the underlying tissues. Indeed, our team has reported that weak currents (only 1-10 mA) promote nerve growth in the leg of an adult rat when applied through acupuncture needles [115, 141, 145, 153]. In China, over 100000 patients with Bell's palsy of the seventh nerve have been reported anecdotally to benefit from EA and plain needling [214]. Perhaps the current of injury caused by needling and generated by the 20--90 mV resting potential across the intact skin promotes nerve regeneration in these cases. It is important to note that in a weak DC electric field, nerves grown in cell cultures will grow branches toward the electrodes [ 1311. Moreover, this growth is maximal in the direction of the negative pole [1311. The papers from our laboratory also show enhanced nerve growth toward the negative pole of the applied DC field [115, 141, 145, 153]. Holes made by needles would also cause a negativity at the site of injury due to the current of injury.
	Regeneration of amputated amphibian limbs has been shown to be enhanced by applied electric fields and currents in the direction of the negative pole [ 17]. Although this has not been shown in adult mammals, there is indirect evidence of its effects in humans. If children suffer accidental amputation of the distal phalanx, it will completely regenerate (with nail, fingerprint, etc.), provided the tissue is kept moist. The latter allows a current of injury which is negative distally and about 1 mA in amplitude [84].
	In paraplegic guinea pigs, DC fields and currents have also been implicated in bone healing, plant growth, embryology, and spinal cord regeneration 1128]. Preliminary studies on normal human volunteers in our laboratory indicate that needling the skin produces a decrease in local skin resistance which lasts 1-2 days [166]. A simple calculation using Ohm's law suggests to us that a small hole created by an acupuncture needle can create a current of injury (10 mA) sufficient for possible benefit to tissue growth and regeneration [17, 141]. It should be noted that these tiny currents would not be sufficient to initiate nerve impulses, and hence the mechanisms shown in Figs. 1 and 2 would not be relevant here.
	Attempts to use Kirlian photography to study acupuncture cannot be trusted, as this method is so fraught with artifacts. Perhaps the most intriguing phenomenon related to the meridians are propagated sensations along the meridians (PSM). In about 10 % of the population, needling causes a sensation to radiate along the meridian away from the needle in a direction inappropriate for the direction of the nerves (i.e., paresthesias should always propagate from proximal to distal, but PSM often goes from distal to proximal). The speed of transmission of PSM is approximately 10 cm per sec, which is 10 times slower than the slowest conducting C-fibers [ 10, 111. Moreover PSM does not follow somatosensory distribution of the nerves or restrict itself to one or two dermatomes. Professor Bossy has proposed a plausible mechanism which does not involve Qi transfer along the meridians but rather a neurological one [24]. He proposes that the neural message travels from the acupoint into the spinal cord and then up and down several spinal segments (i.e., dermatomes) via interneuronal networks in laminae 2 and 3 of Rexed of the dorsal horn. The brain then perceives this as a sensation traveling into these dermatomes, i.e., as an illusion.
1.6.4

Which Nerves Are Activated by Acupuncture?

	Electrophysiological evidence given below indicates that stimulation of muscle afferent fibers (types II and III) produces De Qi sensations [203], which in turn send messages to the brain to release neurochemicals (endorphins, monoamines, cortisol). Perhaps acupoints are the loci of type II and III fibers.
	In a review, Omura emphasized the importance of eliciting strong muscle contractions to optimize AA; this, he says, requires low frequency EA to avoid tetanic contractions 11301. Strong muscle contractions are elicited because the stimulus intensities required to activate the type III afferent fibers must be 5 to 10 times the threshold for the muscle efferents.
	One of the earliest and most clear-cut papers on the subject was published by Chiang in 1973 [44]. In it he showed that the essential correlate of analgesia was a De Qi sensation: the feeling of numbness, fullness, and sometimes soreness [44]. By injecting procaine (2%) into the acupoints L1.4 and L1.10 in humans, he determined that subcutaneous injections did not block I)e Qi sensations, while intramuscular procaine abolished them. Moreover, whenever De Qi was blocked, so was AA. Experiments have been done in animals [27, 55, 149] showing that procaine injections also abolish AA. To rule out the role of circulating compounds released by acupuncture, he also repeated these experiments with an arm tourniquet: when the De Qi persisted, so did the AA.
	Another important finding in Chiang's paper was the lack of target specificity: acupuncture of points in the arm produced equal AA in all parts of the body, as measured by skin analgesia tests [44]. (He did not test the arm itself, or he would have seen a stronger segmental effect there). Two other studies showed the same lack of target specificity in humans in acute laboratory-induced pain [ 103, 106]. This lack of target specificity is consistent with the mechanisms shown in Fig. 2. It must be strongly emphasized here that the authors of the last two papers mentioned may have drawn wrong conclusions from their otherwise excellent studies: they concluded that all the relief experienced was purely a placebo effect, since there was no targeting of the treatment effects to specific pain locations. Yet it is not possible that 60 % of patients could have benefited from placebo: as stated previously, Beecher reports that in acute laboratory-induced pain, placebo only works in 3 % of volunteers [9] and hence the 60% effect in the acute pain studies [106] could not have been mediated by placebo. Since they stimulated true acupoints, they observed widespread AA effects. We interpret all these findings as follows: the acupoint maps are essential for localizing the sites where the best I)e Qi can be achieved (i.e., location of type II and III muscle afferents). In that sense, the points are specific. However, the further claim of traditional Chinese medicine that the points are also targetspecific may not be true.
	The conclusion that point specificity is not total nonsense comes from the many studies on acute pain both in humans and animals in which sham acupuncture produces no analgesia. Here "sham" is used to mean placement of needles in nonacupoints. Remember that Lynn and Perl [ 106] placed needles in true acupoints but inappropriate ones for the pain targets. Their points were not truly sham in that they did not use nonacupoints.
	There have been numerous studies using proper sham acupuncture. One human study acupuncturing the first dorsal interosseous muscle (1.1.4) produced a rise in tooth pain threshold using signal detection theory, while sham acupuncture of the fourth dorsal interosseous muscle produced no analgesia [29]. Another study of the pain threshold in the neck produced similar results 11721. Numerous animal studies have shown the same specificity: in mice [ 147], cats [27, 56], horses [43], rats [ 186], and rabbits [55, 102]: the sham points showed no AA while real points did.
	The most extensive series of experiments on sham acupuncture was performed on rats by Takeshige et al. in Japan. Not only did this group find that nonacupuncture (sham) points failed to produce AA, in contrast to true points in the same animals, but they proceeded to find a plausible explanation [54, 81, 82, 92, 122, 138, 161, 175, 176, 178, 181, 194]. In a series of elegant experiments far too complex to give in detail here, they mapped out an AA inhibitory system in the brain which is activated by stimulation of nonacupoints: this system is activated from nonacupoints via nerves to the posterior hypothalamus, then to the lateral contramedian nucleus of the thalamus, and finally to lateral PAG, where it inhibits the midbrain AA system. (For a review of this extensive research project, see 11761.) Lesioning of this inhibitory system releases the suppressed AA, so that nonacupoints become effective in producing AA. Finally, Toda and Ichioka did an elegant experiment in the rat to show that lesioning of the ulnar nerve had no effect in blocking AA from LI.4 stimulation, but that radial and median nerve lesions abolished AA 11861. Conversely, electrical stimulation of radial and median nerves produced AA, but ulnar stimulation did not [186]. It thus appears that the ulnar nerve does not reach the analgesia sites of the brain. Experiments on nausea and vomiting showed that procaine into Pe.6 blocked the acupuncture effect [49].
	This brings us to the most direct experiments of all: the recording of impulses from the nerves involved in producing AA. Pomeranz and Paley 1149], recording from afferents from LI.4 in mice, found that type II afferents were sufficient to produce AA. But they deliberately avoided activation of pain fibers (types III and IV) in awake mice to avoid stress analgesia. Similar results were reported by Toda and Ichioka, showing that type II afferents were sufficient for AA in the rat 11861, since recruiting types III and IV did not augment the AA.
	Experiments in monkeys, in which A-u and A-]3 fibers (i.e., types I and II) of the tibial nerve were electrically stimulated, resulted in only slight inhibition of pain responses of the spinothalamic pain tract [47]. However, when the stimulus strength was increased to a level which excited A-b (type 111) fibers, a powerful inhibition was observed [47]. Moreover, it should be emphasized that increasing the stimulus strength to excite C fibers (type IV) is not necessary, as it causes unbearable pain in conscious patients.
	Lu [104] showed that types II and III afferents were important in rabbits and cats for AA: dilute procaine (0.1 %) blocked type IV fibers and had no effect on AA, while ischemic or anodal blockade of types II and III fibers abolished AA. Thus, types II and III mediate AA in these two species (all blockades were verified with direct electrical recordings from the blockade nerves).
	Perhaps the best experiment of all was done on humans with direct microelectrode recordings from single fibers in the median nerve while acupuncture was performed distally [203]. When De Qi was achieved, the following was observed: type II muscle afferents produced numbness, type III gave sensations of heaviness, distension, and aching, and type IV (unmyelinated fibers) produced soreness. As soreness is an uncommon aspect of De Qi, we must conclude that the main components of De Qi are carried by types II and III afferents (small myelinated afferents from muscle).
	A study of De Qi on 65 human volunteers supports the existence of these sensations with needling. However, they also reported a confusing finding in the same paper: it seems that sham needling at nonacupoints produces as much De Qi as is elicited from true classical acupoints 1198]. More research is needed to confirm this paradox. If it is true, then acupoints may not be site-specific for AA after all, if AA is indeed always elicited by De Qi. Perhaps this could explain the moderate success rate for AA as compared to sham AA that was achieved in some studies. Unfortunately, as mentioned above, very few studies discuss the De Qi aspect of the treatment parameters used.
	Finally, mention should be made of the sensation sometimes felt by the acupuncturist: the "grab" of the needle by the muscle when proper De Qi is achieved. Recordings of electromyograms around acupoints during l)e Qi have shown pronounced muscle activation accompanied by the therapist's noting the grab of the needle [4].
	The practical importance of all this could be summarized as follows: for AA, it is important to use strong stimulation to achieve De Qi sensations; the acupuncture maps are specific in the sense of helping us find types 11 and Ill fibers needed to obtain De Qi. However, acupoints may not be target-specific, as claimed by meridian theory; the only target specificity occurs from segmental effects of Ah Shi point stimulation, in which there is an additional benefit from spinal segmental endorphins (Fig. 2, cell 7) added to the total body effect of midbrain and pituitary endorphins (Fig. 2, cells 11 and 14). Thus, of the three acupuncture effects - local, meridian, and total body - we have evidence for local (Fig. 2, cell 7) and total body effects (Fig. 2, cells 11 and 14) but so far none for meridian effects.
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  CHAPTER 2

  Mechanisms of Acupuncture Analgesia 
 Produced by Low Frequency Electrical Stimulation 
 of Acupuncture Points

C. Takeshige

2.1

Introduction

	Three noteworthy phenomena have been recognized in surgical acupuncture analgesia (AA) produced by low frequency electrical stimulation of acupuncture points: (1) consciousness is maintained, allowing the patient to talk during surgery, (2) stimulation of specific acupuncture points is essential to maintain analgesia, and (3) analgesia persists long after stimulation has been terminated, allowing the patient to move without pain after surgery. The mechanisms by which AA is produced might be clarified by investigating these phenomena. This review will explore possible mechanisms based on results from animal experiments.
	Consciousness depends on activation of the brainstem ascending reticular activating system (RAS) that produces widespread stimulation of the cerebral cortex and maintains consciousness nonspecifically through the reticular nucleus in the thalamus. The RAS is activated by collateral pathways that diverge from each specific sensory afferent pathway projecting to each sensory cortex. Neurophysiological research has shown that anesthetic drugs used during surgical operations inhibit activity of the RAS. Since consciousness is diminished under this condition, sensory information reaching the sensory cortex is not translated into perception. On the other hand, it is also commonly observed that normally painful stimuli are suppressed on the battlefield and during aggressive sports such as rugby. Such analgesia is thought to be brought about by activation of the descending pain inhibitory system (DPIS) originating from the limbic system and which blocks pain information as it enters the central nervous system. Consciousness can thus be maintained in such a condition. If stimulation of a specific acupuncture point activates the DPIS through a particular pathway connected to the brain system which suppresses pain, it can be assumed that AA is produced by activation of the I)PIS. This assumption has been examined in our laboratories using several animal experiments.
2.2

Classification of Acupuncture Afferent and Efferent Pathways for Producing Acupuncture Analgesia 111-13, 16, 22, 231

	The neuronal structures comprising the AA-producing brain pathway can be identified when microelectrode stimulation induces analgesia in a manner that mimics AA and by tissue ablation that results in subsequent blockage of AA. However, the nature of the analgesia produced depends upon the brain areas stimulated and can be classified into two categories. The first category includes analgesia that is naloxonereversible, disappears after hypophysectomy, persists long after stimulation of the acupoint is terminated, and exhibits individual variation in effectiveness. These features are similar to those of AA. In this category, brain potentials are evoked by stimulation of acupoints in the same areas that produce analgesia. Stimulation of brain areas associated with the second category produces analgesia that is not naloxonereversible, not affected by hypophysectomy, is produced only during stimulation, and exhibits no individual variation in effectiveness. Evoked potentials are not obtained from brain regions producing analgesia of this second category, but nonsynchronized neuronal activities are obtained by stimulation of acupoints 1161.
	Brain regions producing analgesia of the first category appear to comprise an afferent pathway for acupuncture, since the pituitary gland is involved in this analgesia and electrical potentials are evoked in these brain regions by stimulation of acupoints. Similarly, areas producing analgesia related to the second category appear to comprise an efferent pathway for acupuncture, since the pituitary gland is not involved and synchronized electrical potentials are not evoked in these regions by stimulation of acupoints 112, 16, 191. All brain regions producing analgesia associated with the second category seem to be connected to the DPIS; AA is produced by activation of the DPIS, which is excited by stimulation of specific acupoints through a particular pathway connected to the DPIS. This DPIS-producing analgesia related to the second category is defined as the acupuncture efferent pathway, whereas the particular pathway from specific acupoints to the DPIS is defined as the acupuncture afferent pathway.
2.2.1

Acupuncture Efferent Pathway [ 13, 16, 241

	Acupuncture analgesia can be abolished by concurrent lesions of the Raphe nucleus and the reticular paragigantocellular nucleus that are known as the origins of the serotonergic and the noradrenergic descending pain-inhibitory systems. Stimulation of these nuclei respectively produces serotonergic and noradrenergic analgesia of the second category. The final production of AA is induced by activation of these descending pain inhibitory systems. The descending pain inhibitory pathway serves as the acupuncture efferent pathway from the hypothalamic ventromedian nucleus (HVM); it is divided into two parts that connect to the descending serotonergic and noradrenergic systems. The posterior part of the hypothalamic arcuate nucleus (P-HARN) is anatomically connected to the HVM. Analgesia produced by stimulation of both the HVM and the P-HARN is associated with the second category. Synaptic transmission from the P-HARN to the HVM is apparently dopaminergic, since analgesia produced by stimulation of the P-HARN is blocked by lesions of the HVM or by dopamine antagonists (Fig. 1).
  	Fig. 1. Transmitters in the afferent pathway in both AA and non-AA, in the analgesia inhibitory system (upper figure), and in the acupuncture efferent pathway as the descending pain inhibitory systems (bottom figure). AP acupuncture point, D-PAG dorsal periaqueductal central gray, L-PAG lateral periaqueductal central gray, LH lateral hypothalamus, ME median eminence, M-HARN, A-HARN, PHARN medial, anterior, and posterior hypothalamic arcuate nucleus, NAP nonacupuncture point, NAA-AH anterior hypothalamus in the NAA afferent pathway, POA preoptic area, I-PH inferior posterior hypothalamus, L-CM lateral centromedian nucleus of thalamus
 2.2.2

Acupuncture Afferent Pathway 111, 12, 23]

	The acupuncture afferent pathway (Fig. 1) starts from an acupoint, ascends through the contralateral anterolateral tract to the dorsal periaqueductal central gray, and reaches the medial part of the hypothalamic arcuate nucleus (M-HARN). Brain regions belonging to the AA afferent pathway can be identified by exhibition of analgesia of the first group related to anatomically known connections. The rostral and caudal relations between these regions have been identified by the loss of stimulationproduced analgesia of the caudal region that follows lesions of the rostral region. These relations are shown in Figs. 1 and 2 [23].
  	Fig. 2. Acupuncture analgesia-producing system
 	Fig. 3a, b. Location of lesioned and stimulated sites in the arcuate nucleus. The arcuate nucleus is bounded by the broken line. The enlarged figure shows the sites at which lesions abolished AA. Analgesia produced by stimulation (SPA) at the open circles was abolished by hypophysectomy. Afferent SPA at the filled circles was not affected by hypophysectomy. Efferent SPA at the half-filled circles was partially abolished by hypophysectomy. The hypothalamic arcuate nucleus (HARN) indicated by oblique lines was divided into three equal parts: anterior (A-HARN), medial (M-HARN), and posterior (P-HARN)
  2.2.3

Synaptic Connections Between Acupuncture Afferent and Efferent Pathways [25, 281

	The final region of the acupuncture afferent pathway is found in the M-HARN, which is anatomically close to the P-HARN, the initial region of the acupuncture efferent pathway (Fig. 3). Microinjection of the dopamine antagonist haloperidol antagonizes AA dose-dependently, while microinjection of dopamine into the P-HARN induces dose-dependent analgesia. Dopamine thus seems to serve as the neurotransmitter between the M-HARN and the P-HARN, i.e., as the neurotransmitter at the interface between the acupuncture afferent and efferent pathways. This possibility is further supported by neuronal activity in the P-HARN. Neurons in the P-HARN that respond to acupoint stimulation also respond to iontophoretically administered dopamine, whereas neurons in the P-HARN that do not respond to acupoint stimulation also do not respond to iontophoretically administered dopamine [251 (Fig.4).
	A branch of the acupuncture afferent pathway ascending to the M-HARN diverges at the lateral hypothalamus (LH) to reach the pituitary gland. Lesions of brain nuclei near this pathway to the pituitary, e.g., the preoptic area (POA) or the median eminence (ME), abolish AA. Electrical potentials are evoked in these brain areas by stimulation of acupoints, but stimulation of these particular brain structures does not produce analgesia [25, 28] (Figs. 1, 2, 5). Since acupuncture analgesia and pain relief produced by stimulation of the acupuncture afferent pathway to the M-HARN are both abolished by hypophysectomy, [i-endorphin released from the pituitary gland may play an essential role in dopaminergic transmission in the P-HARN [25] (Fig. 5). Microinjection of naloxone to the P-HARN antagonizes AA dose-dependently and microinjection of [3-endorphin or morphine produces analgesia dose-dependently. Analgesia produced by microinjection of [3-endorphin disappears after denervation of the M-HARN, but analgesia produced by microinjection of dopamine to the P-HARN remains [25] (Fig.6). These findings suggest that [3-endorphin might act presynaptically at dopaminergic synapses in the P-HARN. This notion is further supported by the activity of P-HARN neurons. Neuronal activity in the P-HARN that occurs in response to acupuncture stimulation is not affected by iontophoretic administration of morphine or ultramicroinjection of [i-endorphin via picospritzer [22[ (Fig.7).
  	Fig. 4a, b. Rate histograms of two different typical P-HARN neurons in acupuncture-responder rats. One was excited by iontophoretically applied 25n monosodium glutamate (MSG) and 20nA dopamine (DA), and also by acupuncture stimulation. The other was excited by iontophoretically applied 12 nA MSG but inhibited by 5 nA DA and did not respond to acupuncture stimulation, even after IV 20 mg/kg proglumide
 	Since morphine and (I-endorphin act similarly in the P-HARN, (i-endorphin released from the pituitary gland might be the neurohumoral factor acting presynaptically on axon terminals of the M-HARN neurons that innervate P-HARN neurons. Although (i-endorphin microinjected into the P-HARN produces analgesia, electrical stimulation of the POA or ME in the pathway to the pituitary gland does not. Therefore, the amount of (i-endorphin released by such stimulation is not sufficient to activate the P-HARN neurons without afferent impulse from the M-HARN. Morphine and [i-endorphin might also act in other areas of the AA afferent pathway. This possibility was explored by recording electrical potentials evoked by stimulation of the acupoint in the final station of the AA afferent pathway, the M-HARN. Such potentials are enhanced by intravenously administered morphine (0.5 mg/kg) and abolished by hypophysectomy. The abolished evoked potentials are temporarily restored by morphine [ 121 (Fig. 8). Therefore, sites responsive to (i-endorphin released from the pituitary gland might be widespread in the AA afferent pathway. Opioid receptors have also been reported in many regions of the acupuncture afferent pathway [ I, 5, 101.
	Fig. 5. Synaptic transmission between M-HARN and P-HARN in AA and that between A-HARN and P-HARN in non-AA. Two pathways diverge from the lateral hypothalamus (LH) in AA and from the L-PAG in non-AA. Both AA and non-AA are carried by dopaminergic transmission to the P-HARN. Other paths associated with release from the pituitary gland of Iiendorphin (in AA) and ACTH (in non-AA) modulate the dopaminergic systems in the synapse to the P-HARN that is the initial region of the descending pain inhibitory system (DPIS). Convergence is necessary to activate the preoptic area (POA) and median eminence (ME). Hypophysectomy abolished analgesia produced by stimulation of M-HARN and A-HARN. Stimulation of the POA or the ME did not produce analgesia
   	Fig.6. Dose-dependence of analgesia caused by microinjection of dopamine and I3-endorphin into the P-HARN, and effects of denervation of the M-HARN on this dosedependence. Upper control, lower after denervation of the M-HARN
  	Fig. 7. Rate histograms showing typical P-HARN neuron responses in an acupuncture responder rat. The P-HARN neuron excited by iontophoretic 5 nA monosodium glutamate (MSG) did not respond to iontophoretically applied 50 nA morphine (Mor) but was excited by acupuncture stimulation (bottom record)
  	Fig.8. Effects of hypophysectomy and morphine on potentials evoked in the M-HARN by stimulation of an acupuncture point (AP). Column I Control. Evoked potential increased with increasing stimulus. Column 2 Effect of intraperitoneal 0.5 mg/kg morphine on potentials 20 min after application and with 5 min intervals between successive stimuli. Column 3 Effect of hypophysectomy on potentials. Column 4 Effect of IP 0.5 mg/kg morphine on potentials after hypophysectomy. Note close similarity to column 1. Voltage (at 0.05 ms duration) indicated by number at left applies to all columns
 2.3

Stimulation of Specific Acupoints for the Production of AA [23]

	Low frequency (1 Hz) electrical stimulation of the first dorsal finger muscle and the anterior tibial muscle in rats [11, 23], which correspond to the muscles underlying the human LL4 (Hegu) and St.36 (Zusanli) acupoints, produces behavioral analgesia, evaluated in rats by tail flick latency. The intensity of electrical stimulation must be sufficient to cause muscle contraction in order to obtain AA. In contrast, stimulation of other muscles does not produce behavioral analgesia. Hence, the Hegu and Zusanli acupoints seem uniquely able to activate the DPIS through the particular pathway connected to the DPIS [3].
2.4

Differentiation of Acupoints and Nonacupoints by Responses of Central Neuronal Structures 111, 14, 15, 17, 18]

	Potentials can be evoked specifically in the bilateral dorsal areas of the periaqueductal central gray (D-PAG) by stimulating the muscles underlying the Hegu and Zusanli acupoints but not by stimulation of other muscles (Fig. 9). Lesions of the D-PAG abolish AA. Microelectrode stimulation of this region produces analgesia of the first category that can be reversed by either naloxone or hypophysectomy. Stimulation of the auricular levator muscle beneath the X18 (Chihmo) acupoint in rabbits elicits evokes potentials in the D-PAG 111, 23]. Stimulus conditions as stated above which lead to AA were confirmed by potentials in the D-PAG. Therefore, only three acupoints for producing AA have been identified: Hegu, Zusanli, and Chihmo.
	Stimulation of muscles including those beneath Hegu and Zusanli also produces nonspecific potentials bilaterally in the lateral parts of the periaqueductal central gray (L-PAG) [17] (Fig.9). Potentials in the L-PAG are gradually decreased by repetitive 1 Hz stimulation of these muscles and disappear completely 10 minutes after the onset of stimulation [ 15, 17] (Fig. 10). Hence, potentials in the L-PAG are inhibited by such stimulation in a self-inhibiting fashion. Lesions of the L-PAG do not affect AA, but analgesia is produced by stimulation of the rostral L-PAG. This analgesia is largely reversible with dexamethasone, and the dexamethasone-insensitive portion is readily blocked by naloxone or hypophysectomy. Hence, acupoints are connected via the DPAG to the particular pathway that is not self-inhibited during the production of AA. On the other hand, both acupoints and nonacupoints are connected nonspecifically to the other, self-inhibiting pathway via the L-PAG. The latter brain region belongs to a pathway distinct from the AA afferent pathway, whose analgesia production is selfinhibiting (Fig. 11). These results imply that acupoints and nonacupoints can be differentiated by their connections with different analgesia-producing central pathways 114, 171 (Figs.1, 11).
  	Fig.9. Examples of scars produced by electrodes inserted into the D-PAG (upper left) and L-PAG (upper right). Sites of recordings in the D-PAG (lower left) and L-PAG (lower right)
  	Fig. 10. 1.-PAG evoked potentials from a typical rat were gradually depressed and finally abolished by repetitive 1 Hz stimulation of the acupuncture points (left). Those in the D-PAG were not influenced (middle). After lesioning the L-CM, inhibition of evoked potentials in the L-PAG disappeared (right). Numbers by each record indicate time in minutes after start of stimulation
  	Fig. 11. Differentiation of acupuncture and nonacupuncture points by the analgesia inhibitory system.
 2.5

Similarities Between Acupuncture Analgesia and Morphine Analgesia

	Analgesia produced by intraperitoneal 0.5 mg/kg morphine is of a similar degree to that produced by low frequency electroacupuncture. In addition, both types of analgesia are abolished by hypophysectomy, lesions of the AA afferent and efferent pathways, naloxone, and antagonists of transmitters involved in the AA efferent pathway. In addition, individual variations in effectiveness between AA and morphine analgesia are highly correlated. Animals can be classified as responders or nonresponders by the presence or absence of a significant increase (p<0.05) in tail flick latency.
  	Fig. 12. Effect of intrathecal application of antisera to met-enkephalin (left), leu-enkephalin (middle), and dyn (right) on potentials in the D-PAG evoked by acupoint stimulation. Top Control, middle 10 min post application of the antisera of opioids, and bottom recovery 20 min afterward
 2.6

Activation of the Spinal Acupuncture Analgesia Afferent Pathway by Morphine [8, 11, 12, 14, 18]

	Potentials evoked in the D-PAG by stimulation of acupoints are blocked by contralateral lesions of the anterolateral tract or by intrathecal administration of the antiserum to methionine (met)-enkephalin. These potentials are also blocked by naloxone but not by the administration of antisera to leucine-enkephalin or dynorphin [18] (Fig. 12), supporting the involvement of a met-enkephalin pathway activated by morphine. In AA responder animals, dose-response curves of analgesia were obtained for both low and high doses of morphine administered either intraperitoneally or intrathecally. However, in nonresponding animals, only a single dose-response curve for higher doses of morphine was obtained. In AA responders, bilateral lesions of the anterolateral tract or lesions of the D-PAG that is part of the AA afferent pathway abolished dose-dependent responses to low doses of morphine without affecting the dose response to high doses of morphine. Therefore, morphine analgesia produced by lower doses is probably induced by activation of the AA afferent pathway through met-enkephalin receptors in the spinal cord 1181. Such receptors in the spinal AA afferent pathway are likely to be those activated by intraperitoneal morphine at 0.5 mg/kg or intrathecal morphine at 0.05 Vg/rat that produce morphine analgesia to a degree similar to that of AA 18, 111 (Fig. 13). This mechanism may explain the reason for the similarity between AA and morphine analgesia.
	Fig. 13. Morphine analgesia mediated by acupuncture analgesia-producing system
  2.7

Individual Variations in Effectiveness of AA and Morphine Analgesia [21, 271

	After treatment with D-phenylalanine (DPA), an inhibitor of enzymes such as aminopeptidase and carboxypeptidase that degrade met-enkephalin, the strong correlation of individual variations in effectiveness between AA and morphine analgesia disappeared. In other words, AA and morphine analgesia were obtained at similar magnitudes in both responders and nonresponders after treatment with DPA.
	Individual variation in amplitude of evoked potentials in the D-PAG also disappeared after treatment with DPA [27]. Hence, individual variations in effectiveness of both AA and morphine analgesia might be attributed to the activity of enzymes degrading met-enkephalin in the spinal cord. Higher enzyme activity might reduce met-enkephalin levels and block responses to AA, whereas lower activity might increase met-enkephalin levels, activate AA afferent pathways, and facilitate responses to AA.
2.8

Analgesia Produced by Stimulation of Nonacupoints After Lesioning of the Analgesia Inhibitory System [ 11, 15, 17, 26, 28]

	As stated previously, potentials in the L-PAG evoked by stimulation of either acupoints or nonacupoints are self-inhibiting. However, after lesions are made in the lateral centromedian nucleus of the thalamus (L-CM) or parts of the posterior hypothalamus (I-PH), evoked potentials in the L-PAG are not self-inhibited and such stimulation results in pronounced analgesia. Analgesia produced by stimulation of nonacupoints after lesioning of these areas is referred to as nonacupuncture stimulationproduced analgesia (Fig. 11).
	Since analgesia from stimulation of nonacupoints is induced by stimulation of acupoints only after lesions occur in the I-PH or the L-CM, these regions are considered part of an analgesia inhibitory system (AIS) for this type of analgesia (Figs. 1, 11). Thus, the AIS may have an important role in distinguishing between acupoints and nonacupoints, since it inhibits afferent impulses arising from stimulation of nonacupoints but not those arising from stimulation of acupoints.
2.9

Afferent and Efferent Pathways That Produce Nonacupuncture StimulationProduced Analgesia [26]

	Nonacupuncture stimulation-produced analgesia (non-AA) can be blocked by hypophysectomy and lesions of the non-AA afferent pathway. This system is inhibited dose-dependently by dexamethasone but not by naloxone; unlike AA, non-AA does not exhibit individual variations in effectiveness [26]. Potentials in the L-PAG evoked by stimulation of nonacupoints are not abolished by intrathecal administration of antisera to met-enkephalin or leu-enkephalin but are abolished by antiserum to dynorphin (Figs. 1, 12). Hence, dynorphin is believed to be the transmitter of the spinal non-AA afferent pathway [18]. Since dynorphin is not degraded by aminopeptidase or carboxypeptidase, individual variations in effectiveness are not observed in non-AA. Descending pain inhibitory systems such as those found in the acupuncture efferent pathway are common in non-AA and AA. The afferent pathway for this system originates at nonacupoints and ends in the anterior part of the hypothalamic arcuate nucleus (A-HARN) connected to the initial region of the efferent pathway. Lesioning of the AIS augments AA produced by stimulation of acupoints; hence, the acupoint also sends fibers to the non-AA afferent pathway. The augmented component of analgesia is largely antagonized by dexamethasone, and the remainder is antagonized by naloxone [ 17).
  	Fig. 14. a 0.1 mM monosodium glutamate (MS(,) increased firing rate of P-HARN neuron as application time increased from 50 ms to 300 ms. b Firing rate of MSG-responsive neuron was increased by dopamine applied for 100 and 150 ms. This neuron also responded to nonacupoint stimulation (NAPS) after application of proglumide. c Another MSG-responsive neuron did not respond to 100 ins or 900 nis applications of dopamine. This neuron also did not respond to NAPS after application of intravenous 20 mg/kg proglumide. d Microapplication of same dose of ACTH by picospritzer for 100 and 900 nis produced no change (left) in NAPS-responsive neurons in the P-HARN after intravenous 20mg/kg proglumide (right). e Microapplication of ACTH into the P-HARN for 100 or 900 ins produced no change in P-HARN neuron activity (left), but intravenous 0.25 mg/kg ACTH increased firing rate of this P-HARN neuron (right)
 	Lesions of the non-AA afferent pathway block non-AA, and stimulation of the non-AA afferent pathway produces analgesia that is largely reversible with dexamethasone. These lesions are almost completely reversible with dexamethasone plus naloxone (Fig. 11). Transmission between the A-HARN and P-HARN has been found to be dopaminergic, as is that between the M-HARN and P-HARN. Evidence supporting this conclusion is that (1) microinjection of dopamine into the P-HARN produces analgesia dose-dependently and administration of haloperidol antagonizes non-AA dose-dependently, and (2) some neurons in the P-HARN that respond to nonacupoint stimulation when the AIS is inhibited with proglumide also respond to iontophoretically administered dopamine [26] (Fig. 14).
	In contrast, other neurons do not respond after either procedure. The afferent pathway of non-AA from nonacupoints divides into two pathways at the L-PAG: one pathway ascends to the A-HARN and the other ascends to the pituitary gland via the median eminence. Lesions of the latter pathway abolish non-AA, but stimulation of this pathway does not in itself produce analgesia [28] (Figs. 1, 5).
2.10

Pituitary Hormones and Nonacupuncture Stimulation-Produced Analgesia

	Adrenocorticotrophic hormone (ACTH) released from the pituitary gland seems to be essential for dopaminergic transmission between the A-HARN and P-HARN. This follows, since dexamethasone microinjected into the P-HARN antagonizes non-AA dose-dependently, while ACTH administration mimics non-AA dose-dependently [261. Therefore, two neurotransmitters are necessary for transmission between the non-AA afferent and efferent pathways in the arcuate nucleus. Dopamine has been found to act postsynaptically, while ACTH acts presynaptically at this synapse. Evidence in support of these conclusions is that after denervation of the A-HARN, analgesia produced by ACTH microinjected into the P-HARN disappears but that produced by dopamine microinjected into the P-HARN is unaffected [26] (Fig. 15).
	Furthermore, neuronal activities that occur in response to stimulation of nonacupoints during administration of proglumide do not respond to iontophoretically administered ACTH [26] (Fig. 14). Beta-endorphin and ACTH released concomitantly from the pituitary gland might be the presynaptically acting neurohumoral factors in AA and non-AA, producing dopaminergic transmission in the P-HARN (Fig. 5). The possibility that ACTH acts as a neurohumoral factor in other regions of the non-AA afferent pathway has been examined by recording potentials evoked by nonacupoint stimulation after lessoning in the A-HARN, the final station of the non-AA afferent pathway. Such evoked-potentials in the A-HARN are enhanced by intraperitoneal administration of ACTH and are markedly decreased by hypophysectomy. However, these decreased potentials are restored by intraperitoneal administration of ACTH. Consequently, ACTH might act on the afferent pathway of non-AA before entering the A-HARN [22] (Fig. 16).
	Microinjection of ACTH onto sites of the non-AA afferent pathway such as the L-PAG and the anterior hypothalamus produces dose-dependent analgesia. Conversely, microinjection of dexamethasone antagonizes analgesia dose-dependently [23] (Fig. 17). Furthermore, intraperitoneal ACTH produces dose-dependent analgesia, intraperitoneal dexamethasone blocks non-AA dose-dependently, and intravenous ACTH stimulates neuronal activity in some P-HARN neurons 1261. These findings suggest that ACTH acts as a synaptic neurotransmitter and dexamethasone acts as an antagonist at these sites.
2.11

Sites of Inhibition from the AIS in the Non-AA Afferent Pathway [ 15, 171

	Inhibition of evoked potentials and neuronal activity in the L-PAC; induced by nonacupoint stimulation is observed in rostral but not caudal regions of the L-PAG. Similarly, stimulation of the I-PH or the L-CM completely inhibits nonacupoint-evoked potentials in rostra) but not caudal L-PAG 1171. Therefore, the AIS exerts its inhibitory effects in the region between the rostral and caudal L-PAG in the non-AA afferent pathway. Inhibition of potentials in the rostral L-PAG evoked by nonacupoint stimulation during stimulation of the I-PH is abolished by lesions of the L-CM; hence, nonacupoint stimulation activates the I-PH first and then the L-CM [ 171.
	Fig. 15. Control. Dose-response relationships for dopamine and ACTH microinjected into the P-HARN and analgesia produced. Analgesia due to ACTH disappeared after denervation of the A-HARN while that of dopamine remained unchanged
   	Fig. 16. Effect of 0.25 mg/kg ACTH before and after hypophysectomy on potentials in the A-HARN evoked by NAP stimulation in L-CM-lesioned rats. Column I Control potentials were increased with increasing stimulus strength in volts (V, 0.05 ms duration) indicated by numbers at left. Column 2 Potentials 30 min after application of ACTH. Column 3 Effect of hypophysectomy on potentials. Column 4 Effect of 0.25 mg/kg ACTH (IP) on potentials after hypophysectomy
  	Fig. 17. a Dose response of antagonism by dexamethasone microinjected into the L-PAG. b Dose response of analgesia produced by ACTH microinjected into the L-PAG. Ordinate numbers: antagonism (A) and analgesia (B) in percent. Abscissas doses of dexamethasone (A) and ACTH (B)
 2.12

Neurotransmitters in the Analgesia Inhibitory System and Nonacupuncture Stimulation-Produced Analgesia

	Non-AA of the AIS is produced by stimulation of nonacupoints after intraperitoneal treatment with DPA or proglumide, an antagonist of cholecystokinin (CCK), rather than after lesions of the L-CM or I-PH 1201. Activation of the AIS by stimulation of nonacupoints is obvious during spontaneous neuronal activity of the L-CM, which increases markedly 10 minutes after the onset of nonacupoint stimulation. Such enhancement of neuronal activity is blocked by treatment with proglumide, suggesting that CCK is a neurotransmitter in the AIS 12].
	The timing of the onset of enhancement of neuronal activity in the L-CM (Fig. 18) corresponds fairly well with the timing of the onset of self-inhibition of evoked potentials in the L-PAG after the onset of nonacupoint stimulation [ 141 (Fig. 10). This finding is supported by the increase in CCK-like immunoreactivity in perfusate collected from the L-CM with the push-pull method. Stimulation both of acupoints and nonacupoints significantly increased CCK-like immunoreactivity in the L-CM but produced no increase in the cerebral cortex [311 (Fig. 19). After microinjection of proglumide or DPA into the I-PH or L-CM, analgesia is produced by stimulation of nonacupoints. Of several CCK antagonists microinjected into the L-CM, L365,250 was the most effective in producing non-AA. These results further support the suggestion that CCK-8 is a principal neurotransmitter in the L-CM [2].
2.13

Effects of Adrenalectomy on AA and Non-AA 17]

	Acupuncture analgesia and non-AA are abolished 12 and 24 hours after adrenalectomy, respectively. However, both are restored 1 hour after IV or IP administration of 1-2 ml of 5 % NaCl. Sodium ions are required for the action of met-enkephalin and dynorphin in both the AA and non-AA afferent pathways in the spinal cord. Sodium is also needed for the presynaptic actions of [3-endorphin and ACTH in the P-HARN. These conclusions are supported by the abolition of acupoint- or nonacupoint-evoked potentials in either D-PAG or L-PAG, respectively. They are also supported by the analgesia produced following microinjection of [3-endorphin or ACTH into the PHARN after adrenalectomy and by their recovery after application of sodium chloride. Therefore, the adrenal gland plays a prominent role in production of both AA and non-AA by maintaining sodium levels in the blood independently of the action of the pituitary gland.
	Fig. 18. Changes of L-CM neuronal activity during nonacupuncture point stimulation and antagonistic action of proglumide. Neuronal activity (A) during nonacupuncture point stimulation. Ordinate numbers integrated spikes/2 s. Abscissa time in minutes. Time scale 4 min. Effect of IV 20 mg/kg proglumide on neuronal activity changes. Effect of 20mg/kg proglumide 6min prior to onset of nonacupuncture point stimulation on the L-CM neuronal activity. Arrow indicates application of proglumide. Solid lines under records indicate nonacupuncture point stimulation (NAPS)
  	Fig. 19. Effect of 1 Hz peripheral stimulation on release of CCK-like immunoreactivity (CCK-L1) from medial thalamic and cerebral cortex. Dotted Column from thalamus by stimulation of Zusanli, Hatched column from thalamus by stimulation of abdominal muscle, Open column from cortex by stimulation of abdominal muscle. The concentration of CCK-LI in thalamic dialysate before stimulation was lower than the detection limit (5pg/100g)
  2.14

Aftereffects of AA and Non-AA [30]

	Acupuncture analgesia characteristically persists long after termination of acupuncture stimulation. This aftereffect becomes dominant 60 min after stimulation and is still marked at 120 min post stimulation at 1 Hz. The same pattern is observed with non-AA [2] (Fig. 20). The presence of long-lasting effects in both AA and non-AA suggests that an analgesic mechanism is activated without afferent impulses produced by stimulation of acupoints and nonacupoints. As stated earlier, hypophysectomy abolishes both AA and non-AA, and this procedure abolishes potentials in the M-HARN and A-HARN evoked by stimulation of the acupoints and nonacupoints, respectively. However, abolished potentials in these final regions of the AA and nonAA afferent pathways are temporarily restored by intravenously administered morphine and ACTH, respectively. This finding implies that an increased amount of [3endorphin and ACTH results in a longer period of analgesia. Acupoint or nonacupoint stimulation restores the transmission in the regions of the AA and non-AA afferent pathways.
	Fig. 20. a Changes of acupuncture point stimulationproduced analgesia as related to stimulation period (n = 6). b Changes of nonacupuncture point stimulation-produced analgesia as related to stimulation period (n = 6). Ordinate numbers percent increase of tail flick latency, Abscissa time in minutes, Bars under figure indicate stimulation period
  	During electroacupuncture, major increases of Ii-endorphin and ACTH have been detected in peripheral blood [5]. Both peptides show a continual increase up to 80 minutes after termination of acupuncture stimulation. Furthermore, an analgesic effect was induced in cross-circulation recipient rats after electroacupuncture was applied to donor rats [4]. An increase of endorphins in the cerebrospinal fluid after electroacupuncture [91 suggests a correlation between cerebral and peripheral Iiendorphin levels [5]. The characteristic, frequency-analyzed EEG changes in the deep structure of the brain induced by acupoint stimulation of donor rabbits also appears in cross-circulation recipient rabbits [29]. Since met-enkephalin is a putative neurotransmitter in the AA afferent pathway of the spinal cord, ACTH may be the transmitter in the L-PAG and the anterior hypothalamus in the non-AA afferent pathway. Beta-endorphin and ACTH, coreleased from the pituitary gland, are likely to reach levels high enough to activate these regions. Extended periods of stimulation might also activate the AA and non-AA afferent pathways in which excitability may increase due to post-tetanic potentiation without ongoing afferent impulses.
2.15

Conclusions

	Acupuncture analgesia is produced by activation of the DPIS through a specific pathway connected to the acupoints while still allowing maintenance of consciousness. In contrast, the AIS is activated by stimulation of acupoints or nonacupoints, leading to nonspecific inhibition of different interconnected pathways. Therefore, acupoints and nonacupoints can be distinguished by their anatomically distinct brain pathways. The aftereffects of AA might be produced by the actions of an increased amount of (3-endorphin released from the pituitary gland on components of the AA-producing pathway.
References

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  CHAPTER 3

  Opioid and Antiopioid Peptides: 
 A Model of Yin-Yang Balance in Acupuncture 
 Mechanisms of Pain Modulation

J.-S. Han

3.1

Introduction

	At first glance, sharp differences exist between medicinal practices originating in the east and in the west. While Western medicine is more technological, relies on quantitative measurements, and is increasingly evidence-based, Eastern medicine is minimally invasive, relies on qualitative assessments, and remains largely experiencebased. However, one concept shared by both medical systems is that most if not all physiological functions are regulated by activities posessing opposite effects. To consider only a few examples, blood sugar is decreased by insulin and increased by glucagon, calcitonin and parathyroid hormone act in opposing directions to regulate calcium levels in blood and tissues, and, generally speaking, the sympathetic and parasympathetic systems have contrasting functions in regulating many aspects of our internal environment. These phenomena can be regarded as reflections of the yinyang balance described in traditional Chinese medicine. Thus, the "homeostasis" of Western medicine has long been recognized as "dynamic balance" in the classical texts of Chinese medicine.
	The discovery of enkephalins, the first family of endogenous opioids, by Hughes et al. in 1975 [ 1 ] triggered the search for endogenous substrates with antiopioid activities. Ungar et al. [2] were among the first to present evidence for antiopioid substances [AOS]. At present, an array of AOS has been reported, the most widely studied and probably the most potent of which is cholecystokinin octapeptide (CCK-8) [3].
	Studies of the interactions between opioid peptides and antiopioid peptides are of considerable pharmacological and physiological interest, especially when the everincreasing functions of endogenously released peptides are considered. As with all peptides, the endogenous opioids and antiopioids have been best studied in animal models. Using such models, acupuncture (manipulation of metal needles inserted in specific body sites known as acupoints) and electroacupuncture, or EA (electrical stimulation administered via the needles placed at acupoints), have been shown to be reliable approaches for inducing release of endogenous opioid peptides in the CNS [4]. More recently, animal studies have also demonstrated the acupuncture-induced release of antiopioid substances and examined the functional interactions between these opposing classes of peptides in producing acupuncture analgesia (AA). The aims of the present chapter are to review (a) the current understanding of the involvement of endogenous opioid peptides in AA, (b) the role of CCK in determining the effectiveness of AA and its possible mechanisms, and (c) the role of other putative antiopioid peptides in the CNS, including the newly characterized opiate-like peptide orphanin FQ (OFQ) [5] and angiotensin 11.
3.2

Opioid Mechanisms for Acupuncture Analgesia

	The role of endogenous opioids in AA has been examined at three different levels; the opiate receptors, the opioid peptides, and the neural pathways mediating opioid effects.
3.2.1

Opiate Receptors

3.2.1.1

Receptor Blockade

	The first evidence suggesting the involvement of opioid receptors in AA, provided by Pomeranz et al. in 1976 [6] and Mayer et al. in 1977 [7], was that effects of AA in mice and humans could be abolished or at least markedly attenuated by treatment with the powerful opiate receptor antagonist, naloxone. Further studies revealed that naloxone reversibility of electroacupuncture analgesia (EAA) is dependent on the frequency of EA. Thus, the dose of naloxone needed for 50% inhibition (11)s„) of the analgesic effect of EA in the rat is 0.53 mg/kg for 2 Hz EA, 1.02 mg/kg for 15 Hz EA, and 24.0 mg/kg for 100 Hz EA [8]. Since the sensitivity of different types of opiate receptors to naloxone blockade is known to be p>b>x, the relative resistance of 100 Hz EAA to naloxone reversibility suggests the involvement of x opioid receptors in mediating high frequency EA effect. In contrast, since 2 Hz as well as 15 Hz EAA are very sensitive to naloxone, tt and b receptors are implicated.
3.2.1.2

Cross-Tolerance Study

	Cross-tolerance provides another useful clue for identifying the type or subtype of opioid receptors involved in EAA. When rats were given consecutive sessions of 100 Hz EA for 6 h (30 min on, 30 min off) and the tail flick latency (TFL) measured at the end of each session to assess the potential change of EAA with time, analgesia decreased with the prolongation of stimulation, suggesting the development of tolerance. This is not attributable to either tissue damage surrounding the needle tip or depletion of relevant neurotransmitters in the CNS, since the effect of EAA resumed when the EA frequency was lowered to 2 Hz. Similarly, rats made tolerant to 2 Hz EA were still responsive to 100 Hz EA. The lack of cross-tolerance between 2 Hz EA and 100 Hz EA suggests involvement of different types of receptor mechanisms. Further studies revealed that rats made tolerant to 2 Hz EA were still reactive to intrathecal injection of dynorphin A (1-13), a selective x opioid agonist, but not to OMF and DPDPE and selective It and b receptor agonists, respectively [9]. These results are consistent with the suggestion that 2 Hz EAA is mediated by p and b receptors. In contrast, rats made tolerant to 100 Hz EA showed full response to OMF and DPDPE but not to dynorphin A (1-13), implying that 100 Hz EAA is mediated by x opioid receptors (Fig. 1).
	To summarize, 2 Hz EA uses ft and b receptors to induce the analgesic effect, whereas 100 Hz EA is mediated by x opioid receptors. When 2 Hz and 100 Hz or 15 Hz EA are administered alternately for 3 seconds each (the so-called dense-and-disperse mode), all three types of opioid receptors are involved [10]. This is an important example of how basic research has led to improved clinical treatment, since most electrostimulation devices used for EA now include a setting that automatically toggles between high and low frequency output.
3.2.2

Opioid Peptides

	The framework of a three-member opioid peptide family, the enkephalins [1], endorphins [11], and dynorphins [12], remained for more than 2 decades, when Zadina et al. isolated and characterized the novel endogenous lt-selective agonists, the endomorphins [13]. Evidence will be presented to characterize the respective roles of the four opioid peptides involved in EAA.
3.2.2.1

Antibody Microinjection Study

	While receptor blockade and cross-tolerance studies are powerful techniques for identifying the receptor entities that mediate AA, they provide no information as to the chemical nature of the mediators. To solve this problem, we developed the antibody microinjection technique. Antibodies against specific opioid peptides were developed and injected into the brain or spinal cord (Fig. 1). Each of these antibodies would recognize and bind to its target peptide, resulting in selective blockage of the function of the specific peptide by preventing peptide-receptor interaction. Such studies revealed that low frequency (2 Hz) EA analgesia is attenuated by enkephalin antibodies but not by dynorphin antibodies microinjected into the spinal subarachnoid space. In contrast, 100 Hz EAA is markedly attenuated by intrathecal injection of antibodies against dynorphin but not by antibodies against enkephalin [8]. The results provide strong support for the hypothesis that endogenously released enke phalin and dynorphin are responsible for mediating low and high frequency EA effects, respectively. Furthermore, microinjection of [3-endorphin antiserum into the periaqueductal gray (PAG) of rat selectively blocked the analgesic effect induced by 2 Hz EA but not by 100 Hz, suggesting that [i-endorphin plays a significant role in mediating low frequency EAA in the PAG of the midbrain 114, 211.
	Fig. 1. Summary of electroacupuncture frequency-specific release of endogenous opioid peptides. EM endomorphin, [i-EP (t-endorphin, ENK enkephalin, DYN dynorphin, EA electroacupuncture, EOP endogenous opioid peptide, OR opioid receptor
  	In summary, 2 Hz EA uses (i-endorphin in the midbrain and enkephalin in the spinal cord to produce analgesic effects, whereas 100 Hz EA uses dynorphin in the spinal cord (Fig. 1). But what of the newly characterized opioid peptide, endomorphin? In a recent study, we used endomorphin-I (EMI) antiserum in different dilutions for intrathecal injection in a fixed volume of 10µl and found that EM I antiserum could suppress 2 Hz FAA at 1:10 and 1:100 dilutions but not at 1:1000 dilution [151. In contrast, 100 Hz EAA was not affected by EM I antiserum even when undiluted. The data clearly suggest that endomorphin-1 is involved in 2 Hz EAA but not 100 Hz EAA, at least in rat spinal cord.
3.2.2.2

Radioimmunoassay of Spinal Perfusate

	Neuropeptides released from the spinal cord may diffuse into the CSF, where they can be detected by radioimmunoassay (RIA). The CSF level of a peptide is assumed to be related to its rate of release. In experiments with rats, a dramatic increase of immunoreactive (IR) enkephalin was detected during 2 Hz EA but not 100 Hz [ 161. In contrast, 100 Hz EA was accompanied by an increase of IR dynorphin but not IR enkephalin. Similar results were obtained in humans [ 171. Low frequency (2 Hz) electrical stimulation applied on the skin at the hand acupoint Hegu (LI.4) produced a 367 % (p<0.05) increase of a peptide encoded in the enkephalin gene, with no concomitant increase in dynorphin A. In contrast, 100 Hz EA induced a moderate but highly significant 49% (p<0.01) increase in dynorphin A with no change in IR enkephalin. These animal and human findings of RIA-detectable changes of opioid peptides in spinal perfusates are consistent with the results described above from antibody microinjection studies.
3.2.3

Neural Pathways

	Neurons containing [3-endorphin aggregate in the arcuate nucleus of the hypothalamus (ARH). This is in sharp contrast to the widespread distribution of enkephalins and dynorphins in both brain and spinal cord. Focal lesion and stimulation (mechanical, chemical, and electrical) have been used to characterize the neural pathways involved in electroacupuncture analgesia (EAA) that use opioid peptides as mediators.
3.2.3.1

ARH Mediates Low Frequency EA Analgesia

	To identify the neural substrate within the diencephalon, lesions were placed in several nuclei in the thalamus and hypothalamus 118]. Restricted electrolytic lesioning of the ARH or microinjection of kainic acid, which selectively attacks neuronal cell bodies rather than passing fibers, produced a dramatic reduction of EAA induced by 2 Hz, with no effect at 100 Hz EAA. Additional evidence supporting the importance of ARH in mediating low frequency EAA derives from the observation that cross-tolerance exists between 2 Hz EAA and ARH stimulation-produced analgesia [ 19). In fact, the latter could be fully prevented by intrathecal (ITH) administration of naloxone or the 6-selective antagonist ICI 174,864, implying that analgesia induced by ARH stimulation is mediated by the release of endogenous b opioid agonists, most probably enkephalins. Together with results presented above - that intra-PAG injection of antiserum against [3-endorphin prevents 2 Hz EAA - these findings indicate that signals induced by 2 Hz EA reach ARH, which sends axons to PAG to release [3-endorphin, from which site fibers descend to the spinal cord to release enkephalins, resulting in the production of analgesia.
3.2.3.2.

Parabrachial Nucleus Mediates High Frequency EA Analgesia

	Gross anatomical studies have revealed that (a) removal of the whole forebrain (telencephalon and diencephalon) abolishes 2 Hz EAA but not 100 Hz EAA [20] and (b) EAA is totally abolished in spinal rats. It is logical to speculate that the key element for mediating high frequency EAA is located at a supraspinal, intradiencephalic level, i.e., in the lower brainstem.
	On the basis of this reasoning, discrete electric lesions were placed in several candidate areas of the lower brainstem. Electrolytic or kainate lesions placed within the parabrachial nucleus (PBN) were found to produce a selective reduction of the analgesic effect induced by 100 Hz EA without affecting that of 2 Hz EA. On the other hand, intra-PBN injection of glutamate produced profound analgesia [22].
	In contrast to PBN lesions that selectively block high frequency EAA, electrolytic and kainate lesion of the ventral portion of the PAG (vPAG) produce an almost total abolishment of EAA (at 2 Hz or 100 Hz), although the baseline pain threshold (TFL) remained essentially intact. Thus, the vPAG seems to be a common pathway for low and high frequency EAA [22].
	A key question is: why should the ARH be activated by 2 Hz EA and PBN by 100 Hz EA? A likely explanation is that while afferent neural impulses reach widespread areas in the CNS, only those neurons that can follow the frequency of the afferent impulses can be effectively activated.
3.3

CCK-8 and Acupuncture Analgesia

3.3.1

Initial Findings

	In order to study the mechanisms of AA, we established an animal model in the rat [24]. One animal response that attracted our attention was the gradual decline of analgesic effect when EA stimulation was prolonged for more than 3 h. The similarity of this phenomenon to morphine tolerance led us to refer to it tentatively as "acupuncture tolerance." Since the content of opiate-like substances remained high in the brain of rats subjected to this prolonged EA, their tolerance was unlikely due to a depletion of endogenous opiate-like substances. We speculated initially on whether the antiopioid substance (AOS) might act directly as an opioid receptor antagonist or might act via their own receptor to trigger a negative feedback response to dampen the release of opiate-like substance(s).
	A potentially fruitful approach was to test brain extracts from EA-tolerant rats for antiopiate activity. In an in vitro system, mouse vas deferens exhibited a morphineinduced contraction that was antagonized by either naloxone or a brain extract prepared from morphine- or EA-tolerant rats. Brain extract from untreated control rats had no effect. In an in vivo study in the rat, intracerebroventricular (ICV) injections of the same "tolerant" brain extracts produced a powerful suppression of morphine analgesia (25). Further purification yielded a peptide (sensitive to the broadspectrum proteolytic action of pronase) with a molecular weight of around 1000, but the chemical structure was not characterized.
	In a seminar presented at St. Louis University School of Medicine in 1982, 1 was pleased to receive comments from the audience that CCK-8 might well be the AOS mentioned in my talk, since this peptide was already known to antagonize (i-endorphin's stimulation of feeding behavior. Dr. M. C. Benfield kindly provided me with CCK antiserum and Dr. R. Y. Wang enthusiastically encouraged me to test CCK-8 in our studies. This was the starting point of a series of experiments performed in my laboratory aimed at examining the possible role of CCK-8 as an endogenously released AOS in the modulation of opioid analgesia [26-28].
3.3.2

CCK-8 as a Potent Endogenous Antiopioid Peptide

3.3.2.1

Behavioral Studies

	Using the tail flick assay as an index of nociception, a stable level of analgesia induced by morphine or EA can be established. Experiments in rats have shown that ICV or ITH injection of 1-4ng (1-4pmol) of CCK-8 antagonizes EA analgesia or morphine analgesia dose-dependently (Fig. 2) ]3]. The doses of CCK-8 needed for 50 % reversal (ID5O of EA analgesia are 1.0 ng ICV and 1.5 ng ITH, respectively, suggesting that CCK-8 exerts a somewhat more potent antiopioid action in brain than in spinal cord. Corresponding values for antagonizing morphine analgesia were 1.7 ng and 3.1 ng, respectively. The potency of CCK-8 as an opioid antagonist can be compared with that of naloxone. On a molar basis, the dose of naloxone needed for complete antagonism of morphine analgesia (6-30 nmol) is 6000-8000 times greater than the corresponding dose of CCK-8 (1-4pmol).
3.3.2.2

Electrophysiological Study

	The results obtained from behavioral studies appear straightforward and relatively easy to interpret. However, since the end point of nociception depends on the occurrence of a motor response (tail flick, for example), the results may be subject to mis interpretation (analgesia versus motor paralysis). To test this possibility, the phenomenon was examined in pain-related neurons in the CNS using single cell recording techniques. Among the brain nuclei involved in nociception, the nucleus parafascicularis (PF) has received special attention. Most of the PF neurons reveal an increase of spikes in response to noxious stimuli. These spikes are inhibited by subcutaneous injection of morphine and this effect of morphine is reversed by ITH injection of CCK-8. Likewise, the noxious stimulation-induced spikes of PF neurons is suppressed by EA, and this effect of EA is reversed by ICV injection of CCK-8 [29]. Since the results of these electrophysiological studies reproduced almost every aspect observed in behavioral studies, it can be concluded that the antinociceptive effects of morphine or EA can be antagonized by CCK-8 at nanogram doses.
3.3.2.3

Sites of Action in the CNS

	To locate the sites of action of CCK-8 in CNS, microinjection techniques were employed to administer the octapeptide into discrete brain areas at doses equal to 1 %-10% of parenteral doses. For example, microinjection of 0.25ng of CCK-8 into rat PAG produced a 50% decrease of morphine analgesia [30]. This effect of CCK-8 was readily reversed by the CCK receptor antagonist, proglumide, indicating that CCK-8 is indeed acting via CCK receptors. Similar results were obtained when CCK-8 was injected into the amygdala or nucleus accumbens. These nuclei have been shown to be the central sites that mediate morphine analgesia [31, 32].
  	Fig.2. Dose-dependent reversal of electroacupuncture (EA)-induced analgesia (left) and morphine analgesia (right) by ICV or ITH injection of cholecystokinin-8 (CCK-8). In the EA study, eight rats were given EA stimulation of 15 Hz, 3V, 10 min, on hind limb acupoints ST 36 and SP 6. Immediately prior to EA stimulation, four rats received injection of CCK-8; the other four received unsulfated CCK-8 as control. In the morphine study, morphine sulfate, 5mg/kg was injected SC. CCK-8 or unsulfated CCK-8 were injected 25 min after morphine injection 131
 3.3.2.4

Types of CCK Receptors Involved in Antiopioid Activity

	Two types of CCK receptors designated as types A and B have been characterized. When rat brain or spinal cord slices were incubated with 1211 -labeled CCK-8, that can bind to both types of CCK receptors, subsequent incubation with selective CCK-A or CCK-B antagonists demonstrated that the CCK receptors in the PAG, nucleus accumbens, amygdala, and spinal cord of the rat belong to the CCK-B type [33). In contrast, CCK-A receptors appear to predominate in the CNS of the monkey.
3.3.2.5

Types of Opiate Receptor Interacting with CCK Receptor

	Opiate receptors have been classified into three types: µ, b, and x, with all three types mediating analgesic effects. However, CCK-8 suppresses analgesia mediated by the it and x receptors, not that mediated by d receptor [34], findings that have been confirmed by Dickenson et al. [35]. In summary, the results obtained from behavioral, electrophysiological, and morphological studies have amply demonstrated that nanogram levels of CCK-8 can interact with CCK-B receptors in specific sites in the CNS to interfere with the function of Et and x opiate receptors, resulting in antiopioid effects.
3.3.3

Biochemical Mechanisms of Opiate/CCK Interaction

3.3.3.1

Interaction (Cross Talk) at the Receptor Level

	Firstly we used 'H-etorphine, which binds to all three types of opiate receptors, and found that CCK suppresses total opiate receptor binding in a dose-dependent manner [36]. In subsequent studies, we used selective ligands for It, 6, and x opiate receptors and found that CCK-8 decreased the total receptor number (Bmax) of the It receptor without changing its binding affinity (Kd). In contrast, CCK-8 decreased the affinity of the x receptor without changing its Bmax [37]. CCK-8 had no effect on binding characteristics of the d receptor, which is consistent with results obtained in the behavioral studies described above [34].
3.3.3.2

Coexistence of Opiate and CCK Receptors on the Same Neuron

	Electrophysiological experiments were performed on small dorsal root ganglion (DRG) neurons using the whole cell patch clamp technique to record voltage-gated calcium currents. The It and x opioid receptor agonists produced a marked decrease in the calcium current that was readily reversed by CCK-8. The effect of CCK-8, in turn, was reversed by the CCK-B antagonist L-365260, suggesting that CCK-8 acts via the CCK receptor rather than directly as an opioid receptor antagonist [38, 39]. These results favor the interpretation that opioid receptors and CCK receptors coexist on one and the same neuron.
3.3.3.3

Uncoupling of Opiate Receptor from G Protein

	It has been established that GTPy S, the long acting GTP analog, can induce an uncoupling of the opiate receptor from the G protein, resulting in a lowering of the receptor affinity to opiates. Similar activity was found for CCK-8 [41 ]. Since combination of GTPy S with CCK-8 produced no additive effect, it is reasoned that they may act at the same postsynaptic site, i.e., uncoupling the receptor from the G protein and thus lowering the efficacy of signal transduction.
3.3.3.4

Involvement of the Phosphoinositol System

	As mentioned previously, antiopiate effects of CCK-8 are induced only by small doses (ng level), in contrast to large doses, which may induce an analgesic effect. It is of interest that an increase in IP3 production is induced by small, but not large, doses of CCK-8 [40, 41 ]. In addition, evidence that the antiopiate effect of CCK can be reversed by lithium seems to favor the involvement of the phosphoinositol system [42].
3.3.3.5

Interaction at the Intracellular Free Calcium Level

	Three types of experiments were performed to examine the role of intracellular free calcium in mediating CCK-8 actions:
	1. Experiments using rat brain synaptosomal preparations revealed that the suppressive effect of morphine on synaptosoma1 45 Ca uptake is reversible by low concentrations (10-100 nmol) of CCK-8.
	2. Studies with dissociated neonatal rat brain cells demonstrated that "Ca uptake could be suppressed by agonists of all three types of opioid receptors, whereas CCK-8 antagonized the effect produced by µand x- but not b opioid agonists [43], findings that are consistent with in vivo results.
	3. CCK-8 increases intracellular free calcium concentration ([Ca"];) [41], in contrast to the effect of opiates that decrease [Ca"],. This effect of CCK-8 can be observed even in calcium-free medium, suggesting that it is due to mobilization of intracellular calcium stores rather than increased calcium influx. In fact, the increase of intracellular IP, induced by CCK-8 would accelerate the release of free calcium from calcium storage.
3.3.4

CCK in Morphine and Electroacupuncture Tolerance

3.3.4.1

CCK-8 and Morphine Tolerance

	Subcutaneous injection of morphine (5 mg/kg) produced an 89 % increase of CCK-8 content in spinal perfusates, suggesting an increase in CCK release [44]. Further studies revealed that CCK-8 release can be activated by t and x but not 6 opioid ago nists [45]. Continuous injection of morphine for 6 days resulted in an increase in brain content of CCK-8 [28] together with an increase in CCK gene expression 146, 47]. That an increase in CCK biosynthesis and release plays a role in the development of morphine tolerance is inferred from findings that ICV injection of CCK-8 antiserum can reverse, at least partly, the morphine tolerance [48].
3.3.4.2

CCK-8 and Electroacupuncture Tolerance

	Experiments in rats have demonstrated that (a) EA for 1 h produces a marked increase of CCK-8 content in the CSF, suggesting an accelerated CCK release in the CNS, (b) EA for 2 h produces a moderate increase in CCK-8 content in midbrain PAG, suggesting an accelerated enzymatic processing of CCK precursor to form the functionally active octapeptide, and (c) continuous EA for 8 h elicits a significant increase in the abundance of CCK mRNA in the brain, indicating an acceleration of gene expression [49]. That increased biosynthesis and release of CCK-8 plays an important role in the development of EA tolerance is suggested by findings that tolerance induced by continuous EA for 6 h is reversed by ICV injection of antiserum against CCK-8 (Fig. 3) 13, 50].
3.3.5

CCK as a Negative Feedback Mechanism for Opioid Analgesia

3.3.5.1

Efficacy of EA Analgesia Determined by Opioid/CCK Balance in the CNS

	As mentioned in Section 3.2.2.2, the efficacy of EA analgesia correlated positively with the availability of opioid peptides in the CNS 1161. Here we emphasize the negative correlation between EA analgesia and the availability of CCK-8 in the CNS. Using cluster analysis, Liu et at. [51] separated 168 rats into two groups according to their response to EA (100 Hz, 3 mA, 30 min). A demarcation in response to EA was calculated at 50 % increase of tail flick latency (TFL). Rats showing a TFL increase of less than 40% were designated as low responders (LR), while high responders (HR) were those showing an increase of more than 60 %. Spinal perfusion was performed and the perfusate used for measurement of CCK-8 immunoreactivity (IR). No difference was found in the baseline concentration of CCK-8 in spinal perfusate between LR and HR. A marked difference, however, was found in CCK-8 levels during the period of EA stimulation. While HR showed no significant increase in CSF CCK-8 levels, the LR showed a dramatic increase, suggesting an immediate and robust release of CCK-8 from the spinal cord. It is thus clear that LR release a large amount of CCK-8 during EA stimulation (to antagonize opioid analgesia). In contrast, those rats producing no increase in CCK-8 release are the HR. CCK-8 in the CNS thus functions as a brake, or negative feedback mechanism, limiting the magnitude of EA analgesia. The sensitivity and extent of the feedback mechanism form the key determinants for the efficacy of EA analgesia.
  	Fig. 3. Reversal of electroacupuncture (EA) tolerance by ICV injection of CCK-8 antiserum. Twenty rats were given continuous EA stimulation of 15 Hz, 3V, 6h. Thirty minutes after cessation of EA, 10 rats received ICV injection of CCK-8 antiserum, while 10 rats received normal rabbit serum as control. All rats were given EA, 15 Hz, 3V, 10 min, at 0.5, 3.5, and 7.5 h after the ICV injection. TFL tail flick latency. ""P<0.01 relative to control 13]
 	Taken together, the findings give rise to the following description: EA stimulation accelerates the release of a whole array of neurotransmitters, including the endogenous opioid peptides. The latter in turn stimulate relevant neurons to release CCK-8 as a negative feedback mechanism. This model is supported by findings that morphine-induced spinal CCK-8 release can be totally abolished by the intrathecal injection of the opiate receptor blocker, naloxone [52]. On the other hand, a direct activation of CCK neurons by EA stimulation cannot be completely ruled out.
	Zhang et al. [54] made a detailed study to clarify whether the rat phenotypes HR and LR are genetically determined. They found a strain (P77PMC) derived from Wistar rats that exhibits genetically determined audiogenic seizures. These rats also happen to exhibit an extraordinarily high analgesic response to 100 Hz EA. Radioimmunoassay (RIA) revealed that brain CCK-8 content is approximately 50 % lower in this rat strain as compared to Wistar rats [54], a finding that may serve as the common denominator for the high response to EA and the high vulnerability to acoustically evoked seizures in these animals.
3.3.5.2

Effect of CCK Gene Manipulation on the Efficacy of EA Analgesia

	P77PMC rats that exhibit both audiogenic epileptic seizures and an extraordinarily high analgesic response to EA were used for gene manipulation studies in which brain content of CCK-8 was altered. Since the brain level of CCK-8 is very low in these rats, we tried to correct this genetic defect by ICV injection of the pSV2 expression vector containing an insert of CCK cDNA (pSV2-CCK). An increase of brain CCK content, appearing 2-4 days after the ICV injection of pSV2-CCK, was accompanied by a decrease in seizure attacks [53] as well as a lowered response to EA analgesia [28]. These effects reverted to preinjection levels in 9 days. In another experiment, LR rats - identified from a large population - were given ICV injections of antisense CCK expression vector (pSV2-CCK"'). A decrease in brain CCK-8 content observed 4-6 days after the ICV injection was accompanied by a marked augmentation of EA analgesia, an effect that subsided in 9 days [55]. The results indicate that effects of EA analgesia can be modulated by manipulation of genes that encode opioid or antiopioid peptides, a phenomenon that fits the concept of yin-yang balance in traditional Chinese medicine.
3.4

Other Antiopioid Peptides

3.4.1

Orphanin FQ and Nocistatin

	Since the discovery of three families of opioid peptides in the 1970s, scientists have not ceased looking for other endogenous opioid peptides and their receptors. The successful cloning of the b opioid receptor in 1993 led to the discovery of an opioid receptor-like (ORLI) receptor in 1994 [56]. While the ORLI receptor shows approximately 50 % identity with the It, d, and x opioid receptors, it has a very low affinity with typical opioid ligands; hence it was also referred to as the "orphan receptor." An endogenous ligand for ORLI receptor, characterized in 1995 on the basis of its hyperalgesic effect in mice after ICV injection, was named orphanin FQ (OFQ) or nociceptin [5, 56]. Subsequently, it was observed that the apparent hyperalgesic effect of OFQ/nociceptin in mice was in fact a reversal of opioid-mediated stress analgesia. This finding led to the notion that OFQ might belong in the category of antiopioid peptides, at least in brain. We undertook a detailed survey to ascertain the effects of exogenously injected OFQ on morphine analgesia and EA analgesia and the relevant role played by endogenously released OFQ in the CNS.
3.4.1.1

OFQ in Morphine Analgesia and Morphine Tolerance

	When injected into the cerebral ventricle of the rat, OFQ shows no significant direct effect on baseline TFL at any dose between 4 frnol and 10 nmol, but it antagonizes morphine-induced analgesia in a dose-dependent manner over a range 0.4-50 nmol. Injected intrathecally, OFQ displays an analgesic effect and potentiates morphine analgesia [57], suggesting opposite roles for OFQ in spinal cord and brain.
	In order to study the possible role of endogenous OFQ in the development of morphine tolerance, rats made tolerant to morphine were given an ICV injection of antiserum against OFQ to sequester putative OFQ from the synaptic cleft. Intracerebroventricular injection of OFQ antiserum but not of normal rabbit serum restored the sensitivity to morphine, suggesting that endogenously released OFQ in the brain plays an important role in the mechanisms underlying morphine tolerance (58]. In a recent study, Yuan et al. [59] administered increasing doses of morphine to rats for 5 days and found a gradual increase of OFQ content in the PAG and amygdala, up to 50 % more than controls, and more than 50 % increased levels of OFQ in the cerebroventric- ular perfusate, suggesting increased biosynthesis and release of OFQ in the brain.
	These results imply that OFQ in brain is antagonistic to morphine-induced analgesia. It may also play an important role in the development of morphine tolerance, forming a link - in addition to CCK - in the negative feedback control for morphine analgesia.
3.4.1.2

OFQ in EA Analgesia and EA Tolerance

	That brain OFQ may also play an antagonistic role in EA analgesia is supported by three lines of evidence: (a) analgesia induced by 100 Hz EA, as measured by radiant heat tail flick latency, is antagonized by ICV injection of OFQ in a dose-dependent manner [60], (b) EA analgesia is potentiated by ICV injection of antisense oligonucleotides complementary to the OFQ receptor, possibly by interfering with the expression of OFQ receptors in brain [60], but is not affected by injection of mis-sense oligonucleotide [60], and (c) LR rats were converted to HR by the ICV injection of antiserum against OFQ at 1:1 and 1:10 dilutions but not at 1:100; in addition, HR rats changed to LR following intrathecal injection of OFQ antiserum at 1:1 and 1:10 dilutions but not at 1:100 [58]. Taken together, these results support the notion that endogenous OFQ plays contradictory roles in brain versus spinal cord in affecting EA analgesia. In other words, while brain OFQ is partially responsible for the LR phenotype in rats, spinal OFQ may be a determining factor for the HR phenotype.
	Tian et al. studied the role of brain OFQ in the development of EA tolerance [58]. Tolerance to EA analgesia can be induced by continuous administration of EA for 6 h (acute EA tolerance) or by one session of EA (30 min) per day for 6 consecutive days (chronic EA tolerance). Both acute and chronic EA tolerance can be reversed by ICV injection of IgG antiserum against OFQ. These results suggest that brain OFQ is recruited to function as an antiopioid peptide within a period of 6 h, and the effect of OFQ may last as long as 24 h and accumulate gradually during a period of 6 days, thus contributing to the formation of chronic EA tolerance.
3.4.1.3

Nocistatin: Endogenous Antagonist for OFQ/Nociceptin?

	It was of interest that the nociceptin precursor designated as nocistatin [61] comprises another bioactive peptide that blocks OFQ-induced allodynia and hyperalgesia in mice. We were interested in determining whether ICV nocistatin would reverse the antimor- phine effect of OFQ in rats, using TFL as nociceptive index. Nocistatin ICV produced no significant changes in basal TFL nor did it affect morphine analgesia. However, it significantly reversed the antagonistic effect of OFQ on morphine analgesia. The doseresponse curve was bell-shaped and the most effective dose was 0.5 ng [62]. According to Okuda-Ashitaka et al. 1611, nocistatin does not bind to the OFQ receptor, although it does bind to membranes of mouse brain and spinal cord with a high affinity in a saturable manner, suggesting the existence of its own receptor. The occurrence of two peptides with opposite functions in the same precursor protein would certainly engender considerable interest from the viewpoint of yin-yang balance.
3.4.2

Angiotensin II

	Kaneko et al. purified an antiopioid substance from bovine brain that was characterized as a peptide chemically identical with angiotensin II (A 11) [63]. In rats, we injected A II ICV into CSF of brain and ITH into spinal cord and found that A II antagonized morphine analgesia dose-dependently in brain but not spinal cord [64]. Further studies revealed that A 11 antagonizes morphine analgesia in the PAG of the midbrain but not in the nucleus accumbens [65], suggesting that PAG is an important site for A II to exert an antiopioid effect.
3.4.2.1

Involvement of Brain A II in EA Tolerance

	To assess the role of endogenous A II in the development of EA tolerance, rats were given ICV injections of A If antiserum or the A II antagonist, saralasin. The antiserum as well as the antagonist led to postponement or reversal of EA tolerance, while radioimmunoassay revealed 1.7-fold (at I h continuous EA), 3.3-fold (2 h), and 1.3- fold (6h) increases in CSF content of immunoreactive A II [66]. The results suggest that synthesis and release of brain A II contribute to the decreased efficacy of EA in producing analgesia when EA stimulation is prolonged.
3.4.2.2

Involvement of Brain A II in Morphine Tolerance

	Acute morphine tolerance was induced in the rat by six successive injections of morphine at 2-hour intervals. Similar to the findings with EA-induced tolerance described above, acute morphine tolerance was postponed by ICV injection of either A 11 IgG or saralasin [67]. Chronic tolerance to morphine was achieved by injecting increasing doses of morphine 3 times a day for 5 days. This tolerance was partially (50 %) reversed by ICV injection of A II IgG [67]. Radioimmunoassay revealed a 1.2- fold increase in CSF content of A II in rats receiving three or six successive injections of morphine. Likewise, repeated administration of morphine for 3 or 5 days produced 1.1-fold and 2.8-fold increases of CSF A 11 relative to the control level [67].
	Observation of the dynamic changes in A II biosynthesis induced by long-term EA stimulation revealed that: (a) CSF content of A II increased within 1 h, suggesting an accelerated release, (b) brain content of A 11 started to increase at 2 h, (c) the A II peak in the gel filtration profile of brain extract shifted markedly to the right after 3 h of continuous EA stimulation, suggesting a shift from the larger, precursor molecule angiotensinogen to the smaller A II molecule [68], and (d) a significant increase of angiotensinogen mRNA was observed after continuous EA for 6h or after repeated injections of morphine for 4 consecutive days [69].
3.4.2.3

Spinal A II: Antagonist of 100 Hz EA

	We reported in our first study that A II antagonizes morphine analgesia after ICV injection but not after ITH injection [64]. Of related interest, we subsequently found that ITH administration of the A II antagonist, saralasin, produces a significant augmentation of the analgesic effect induced by 100Ifz EA analgesia but not that resulting from 2 Hz or 15 Hz EA [70]. In addition, only 100 Hz EA produces a significant increase in the release of A II in spinal cord. Since 100 Hz EA is known to trigger the release of dynorphin in spinal cord, it can be inferred that spinal A II plays a negative feedback role in dynorphin-induced analgesia but not in enkephalin- or morphineinduced analgesia.
3.4.2.4

Mechanisms Underlying the Antiopioid Effect of A II

	Several lines of evidence suggest that A II exerts its antiopioid effect at a postreceptor site rather than at the opiate receptor level: (a) A II does not bind to opiate receptors to a significant extent, as determined by radio receptor assay [70], (b) ICV A II increased brain content of cyclic AMP, whereas the level of this cofactor was decreased by SC morphine [71 ], and (c) A II increased synaptosomal "Ca uptake and completely reversed the morphine-induced decrease in Ca uptake [72].
3.5

Concluding Remarks

	While only about a dozen classic neurotransmitters have been identified, neuropeptides with synaptic modulatory effects may well exist in 10-fold greater numbers. Interactions among the neuropeptides within the narrow synaptic cleft is welldocumented, with additive, synergistic, and antagonistic effects being described. Studies of two families of peptides, the opioids and the antiopioids, as manifested in pain control are proving to create an excellent model for understanding neuropeptide interactions.
	It is theoretically interesting to explore the varied underlying mechanisms by which neuropeptides have evolved into groups with opposite functions. We know, for example, that the opioid peptide dynorphin and the putative antiopioid peptide OFQ have 50 % homology in their amino acid structures [5], suggesting a common origin at the genomic level. We also know that adrenocorticotropic hormone (ACTH) and (-endorphin are derived from the common precursor, POMC, and antiopioid activity is one the many functions of ACTH [73]. Equally interesting is that when the carboxy- terminal 4 amino acids of (3-endorphin (1-27) are truncated, this peptide's function changes from opioid to antiopioid [74]. Similarly, as discussed in Section 3.4.1.3, nociceptin (also known as OFQ) has an action opposite from that of its precursor peptide, nocistatin.
	It is also of interest that, although no structural similarity has been found between CCK-8, A II, and OFQ, a functional synergism was revealed to exist between CCK-8 and A II [75] and between CCK-8 and OFQ (Yuan L et al., unpublished observation). In contrast to the heterogeneity in chemical structure among antiopioid peptides, most opioid peptides bear a common N-terminal structure of Tyr-Gly-Gly-Phe, thus an interaction of either synergism or antagonism between them becomes plausible.
	Unlike exogenously administered chemical agents, the dose of which can be readily varied by several orders of magnitude, the endogenous release of neurotransmitters and neuropeptides is limited to a narrower physiological range. However, thanks to the evolutionary development of synergistic mechanisms, amplification of function can be reached by the simultaneous release of several related transmitters or peptides. The biological economy of these mechanisms is clear. One can safely predict that the biochemical mechanisms underlying neuropeptide interactions will be a major target of research in this millennium and that such research is likely to result in important medical applications.
	Acknowledgement. This work was supported by the National Natural Science Foundation of China and a grant from the U. S. National Institute of Drug Abuse (DA 03983).
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	29. Bian JT, Sun MZ, Xu_MY, Han JS (1993) Antagonism by CCK-8 of the antinociceptive effect of electroacupuncture on pain-related neurons in nucleus parafascicularis of the rat. Asia Pacific Pharmacol 8:90-97
	30. Li Y, Han JS (1989) Cholecystokinin octapeptide antagonizes morphine analgesia in periaqueductal gray of the rat. Brain Res 480:105-110
	31. Zhou ZF, Du MY, Jian Y et al (1981) Effect of intracerebral microinjection of naloxone on acupuncture- and morphine-analgesia in the rabbit. Sci Sinica 24:1166-1178
	32. Zhou ZF, Xuan YT, Han JS (1984) Analgesic effect of morphine injected into habenula, nucleus accumbens, or amygdala of rabbits. Acta Pharmacol Sin 5:150-153
	33. Pu SF, Zhuang HX, Han JS (1994) CCK-8 antagonizes morphine analgesia in nucleus accumbens of the rat via the CCK-B receptor. Brain Res 657:159-164
	34. Wang XJ, Wang XM, Han JS (1990) CCK-8 antagonize opioid analgesia mediated by It- and x- but not b-receptors in the spinal cord of the rat. Brain Res 523:5-10
	35. Dickenson AH, Sullivan AF, Magnuson DS (1992) CCK and opioid interaction in the spinal cord. In: CT Dourish, SJ Cooper, SD Iversen et al (eds) Multiple CCK receptors in the CNS. Oxford University Press, Oxford, pp 503-5 10
	36. Wang XJ, Fan SG, Ren MF, Han JS (1989) Cholecystokinin-8 suppressed 3H-etorphine binding to rat brain opiate receptors. Life Sci 45:117-123
	37. Wang XJ, Han JS (1990) Modification by CCK-8 of the binding of p-, b-, and x opioid receptors. I Neurochem 55 1379-1382
	38. Liu NJ, Xu T, Xu C, Li CQ et al (1995) Cholecystokinin octapeptide reverses It opioid receptormediated inhibition of calcium current in rat dorsal root ganglion neurons. J Pharmacol Exp Ther 1995 275:1293-1299
	39. Xu T, Liu NJ, Li CQ et al (1996) Cholecystokinin octapeptide reverses the Y. opioid receptormediated depression of calcium current in rat dorsal root ganglion neurons. Brain Res 730:207-211
	40. Zhang LJ, Lu XY, Han JS (1992) Influence of CCK-8 on phosphoinositide turnover in neonatal rat brain cells. Biochem 1 285:847-850
	41. Zhang LJ, Wang XJ, Han IS (1993) Modification of opioid receptors and uncoupling of receptors from G protein as possible mechanisms underlying suppression of opioid binding by CCK-8. Chin Med Sci J 8:1-4
	42. Zhang LJ, Han JS (1994) Regulation by lithium of the antagonistic effect of CCK-8 on ohmefentanyl-induced antinociception. Neuropharmacol 33:123-126
	43. Wang IF, Ren MF, Han JS (1992) Mobilization of calcium from intracellular store as a possible mechanism underlying the antiopioid effect of CCK-8. Peptides 13:947-951
	44. Zhou Y, Sun YH, Zhang ZW et al (1993) Increased release of immunoreactive CCK-8 and enhancement of electroacupuncture analgesia by CCK-8 antagonist in rat spinal cord. Neuropeptides 24:139-144
	45. Sheng S, Tian JB, Han JS (1995) Electroacupuncture induces spinal CCK release via p- and x opioid receptors. Chin Sci Bull 40:555-557
	46. Pu SF, Xhuang HX, Han JS (1994) CCK-8 gene expression in rat amygdaloid neurons: Normal distribution and effect of morphine tolerance. Mol Brain Res 21:183-189
	47. Zhou Y, Sun YH, Zhang ZW, Han IS (1992) Accelerated expression of CCK gene in the brain of rats rendered tolerant to morphine. NeuroReport 3:1121-1123
	48. Ding XZ, Fan SG, Zhou JP, Han JS (1986) Reversal of tolerance to morphine analgesia but no potentiation of morphine-induced analgesia by antiserum against CCK-8. Neuropharmacol 25: 1155-1160
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	51. Liu SX, Luo F, Shen Set al (1999) Relationship between the analgesic effect of electroacupuncture and CCK-8 content in spinal perfusate in rats. Chin Sci Bull 44:240-243
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	53. Zhang LX, Wu M, Han JS (1992) Suppression of audiogenic epileptic seizure by intracerebral injection of a CCK gene vector. NeuroReport 03:700-702
	54. Zhang LX, Li XL, Wang L, Han JS (1997) Rats with decreased brain CCK levels show increased responsiveness to peripheral electrical stimulation-induced analgesia. Brain Res 745:158-164
	55. Tang NM, Dong HW, Wang XM et al (1997) Cholecystokinin antisense RNA increases the analgesic effect induced by electroacupuncture or low dose morphine: Conversion of low responders into high responders. Pain 71:71-80
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	58. Tian JH, Zhang W, Fang Y et al (1998) Endogenous orphanin FQ: Evidence for a role in the modulation of electroacupuncture analgesia and development of tolerance to analgesia produced by morphine and electroacupuncture. Br J Pharmacol 124:21-26
	59. Yuan L., Han Z, Chang JK, Han JS (1999) Accelerated release and production of orphanin FQ in brain of chronic morphine tolerant rats. Brain Res 826:330-334
	60. Tian JH, Xu W, 7-hang W et al (1997) Involvement of endogenous orphanin FQ in electroacupuncture-induced analgesia. NeuroReport 8:497-500
	61. Okuda-Ashitaka E, Minami T, Tachibana Set al (1998) Nocistatin, a peptide that blocks nociceptin action in pain transmission. Nature 392:286-289
	62. Zhao CS, Li BS, Zhao GY et al (1999) Nocistatin reversed the effect of orphanin FQ nociception in antagonizing morphine analgesia. NeuroReport 10:297-299
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	64. Wang KW, Han JS (1987) Angiotensin 11 antagonizes morphine analgesia: Effective by intracerebroventricular injection but not by intrathecal injection. Chinese Sci Bull 33:123-128
	65. Wang XM, Ilan JS (1989) Antagonism to morphine analgesia and involvement in morphine tolerance of angiotensin 11 in periaqueductal gray of the rabbit. Chinese Sci Bull 33:149-152
	66. Wang KW, Han JS (1989) Evidence for involvement of brain angiotensin 11 in tolerance to electroacupuncture analgesia in rats. Chin J Appl Physiol 5:32-36
	67. Wang KW, Han JS (1989) Evidence for brain angiotensin 11 being involved in morphine tolerance in the rat. Chin J Pharmacol Toxicol 3:7-11
	68. Wang KW, Han JS (1999) Accelerated synthesis and release of angiotensin 11 in the rats brain during electroacupuncture tolerance. Sci Sinica (B) 33:686-693
	69. Gao RW, Wang KW, Han JS (1989) Accelerated angiotensinogen gene expression in the brain of the rat made tolerance to morphine and electroacupuncture analgesia. Acta Physiol Sin 4 1:299-303
	70. Sheng S, Li J, Wang XM et al (1989) Angiotensin 11 release and antielectroacupuncture analgesia in spinal cord. Acta Physiol Sin 41:179-183
	71. Wang KW, Han JS (1989) Possible mechanisms of the antiopioid activity of angiotensin II. J Beijing Med Univ 21:7-9
	72. Wang XM, Wang XJ, Han JS (1989) Antagonistic effects of angiotensin 11 and morphine on synaptosomal calcium uptake. Acta Physiol Sin 41:179-183
	73. Smock T, Fields HL (1989) ACTHI-24 blocks opiate-induced analgesia in the rat. Brain Res 212:202-206
	74. Hammonds RG, Li CH (1984) Beta-endorphin (1-27) is an antagonist of beta-endorphin analgesia. Proc Nall Acad Sci (USA) 81:1389-1390
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  CHAPTER 4

  The Past, Present, and Future of Meridian 
 System Research

C. Shang

4.1

Acupuncture and the Meridian System

	In 1996, the U.S. Food and Drug Administration reclassified acupuncture needles and substantially equivalent devices from class III (premarket approval, investigational use) to class II (special controls), which includes medical devices for general use such as scalpels and syringes [ 1 ]. Hundreds of randomized controlled trials on acupuncture have been published [2]. Positive results of acupuncture were demonstrated in a variety of conditions such as renal colic [3], migraine [4], osteoarthritis [5], Raynaud's syndrome [6], stroke [7, 8], and low sperm quality [9]. A systematic review of the high quality randomized controlled trials for acupuncture antiemesis showed consistent positive results across different investigators, different groups of patients, and different forms of acupuncture point stimulation such as electroacupuncture, laser, acupressure, and manual acupuncture [10]. The success of acupuncture has sparked many studies on the nature of the meridian system - the foundation of traditional acupuncture theory. According to the Standard Acupuncture Nomenclature proposed by the World Health Organization (WHO) [11], there are about 400 acupuncture points and 20 meridians/vessels connecting most of the points. Since the 1950s, it has been discovered and confirmed by researchers in several countries with refined techniques [12] that most acupuncture points correspond to the high electric conductance points on the body surface [13-17] and vice versa [18]. The high skin conductance of the meridian system is further supported by the finding of a high density of gap junctions at the sites of acupuncture points [19-22]. Gap junctions are hexagonal protein complexes that form channels between adjacent cells. It is wellestablished in cell biology that gap junctions facilitate intercellular communication and increase electric conductivity. Acupuncture and meridian points have also been found to have higher temperature [23], metabolic rates, and carbon dioxide release [24].
4.2

Neurobiology and Acupuncture

	In acupuncture analgesia, the peripheral nervous system has been shown to be crucial in mediating the effect. The analgesia can be abolished if the acupuncture site is affected by postherpetic neuralgia [25] or injection of local anesthetics [26]. In other effects of acupuncture such as antihyperglycemic effects, studies have shown that local blockade of peripheral nerves or denervation did not interfere with the acupuncture effect [27]. In the 1970s, the relation between cerebral cortex and acupuncture alteration of visceral function was explored by examining the cortical evoked potentials, single unit discharges, and neurochemistry associated with acupuncture. For example, the projecting area of Pe. 6 was mapped at the cortex and found to overlap with the cortical splanchnic projection area. It was proposed that the cerebral cortex plays an important role in the mechanism of acupuncture inhibition of visceral pain [28]. These studies brought forth the meridian-cortex-viscera correlation hypothesis [29], which states that the meridian system (1) is an independent system connected via the nervous system to the cerebral cortex and (2) acts through neurohumoral mechanisms [30]. Recently, the activation of visual cortex by stimulation of BI. 67 was mapped by functional MRI [31]. The result showed that the activation of visual cortex by stimulation of Bl. 67 - a point at the little toe used to treat eye-related disorders - is similar to that of visual light stimulation. A generalized acupoint-brainorgan model was proposed in which acupuncture stimulates the corresponding brain cortex via the nervous system, thereby controlling the chemical or hormone release to the disordered organs for treatment.
	In the mid-1970s, the discovery of endorphin induction in acupuncture analgesia and its blockade by naloxone marked a milestone in establishing the validity of acupuncture in mainstream science [32, 33]. Animals that respond poorly to acupuncture analgesia can be rendered good responders by treatment with D-phenylalanine, which inhibits the degradation of met-enkephalin [34]. A close relation between acupuncture and nervous system is also indicated by the considerable overlap between acupuncture points and trigger points - points of maximum tenderness in myofascial pain syndrome [35]. These results have led some practitioners to believe that the meridian system as described in the classic acupuncture literature does not exist and that all the effects of acupuncture are mediated through the nervous system 136, 37]. Other scholars regard the neurally mediated acupuncture phenomena as possibly "minor or secondary effects" and "not the central core of the mechanism of acupuncture" [38]. The neurohumoral theory of acupuncture has been mostly descriptive, with little predictive power.
4.3

Developmental Biology and the Meridian System

	The traditional concepts of the meridian system have been studied from the perspective of morphogenesis. The relation between the meridian system and embryogenesis has been noted for decades [39]. The "gap junction embryonic epithelial signal transduction model" in the mid-1980s [19] proposed that the meridian system contains relatively underdifferentiated epithelial cells connected by gap junctions which transduce signals and play a central role in mediating acupuncture effects. The morphogenetic singularity theory [40] published in the late 1980s applied the singularity theory of mathematics to explain the origin, distribution, and nonspecific activation phenomena of the meridian system, as described below.
4.3.1

Acupuncture Points Are Singular Points in the Surface Bioelectric Field

	Epithelia usually maintain a 30-100mV voltage difference [41]. This voltage is the potential difference across cell layers, not membrane potential. An acupuncture point with high density of gap junctions and high electric conductance will also have local maximum electric current density - a converging point of surface current. This is a singular point of abrupt change in electric current flow. A singular point is a point of discontinuity as defined in mathematics and indicates a point of abrupt transition from one state to another. Small perturbations around singular points can have decisive effects on a system. As James Maxwell observed: "Every existence above certain rank has its singular points... At these points, influence whose physical magnitude is too small to be taken account of by a finite being may produce results of the greatest importance" [42]. The electromagnetic field pattern on the human scalp mapped by a superconducting quantum interference device (SQUID) [43] shows a singular point at the surface electromagnetic field where the surface magnetic flux trajectories converge and enter the body. This point coincides with the acupuncture point GV20 Baihui (Dr. Magnus Lou, personal communication). The converging pathway of magnetic flux on the scalp coincides with the governor vessel in the meridian system. This is a separatrix dividing the surface magnetic field into two symmetrical domains of different flow directions. A separatrix is a trajectory or boundary between different spatial domains (44] and often connects singular points. Morphologically, the governor vessel is also the axis of symmetry on the scalp. This pattern is consistent with the pattern of the meridian system but different from the distribution of any major nerve, lymphatic, or blood vessel on the scalp.
4.3.2

The Role of Electric Field in Growth Control and Morphogenesis

	A variety of cells are sensitive to electric fields of physiological strength [45]. Somite fibroblasts migrate to the negative pole in a voltage gradient as small as 7 mV/mm [46]. Asymmetric calcium influx is crucial in the migration, which can be blocked or even reversed by certain calcium channel blockers and ionophores [47]. In most cases, there is enhanced cell growth toward the cathode and reduced cell growth toward the anode in electric fields of physiological strength [48, 49]. Fast-growing cells tend to have relatively negative polarity. This polarity is due to the increased negative membrane potential generated by the mitochondria at a high level of energy metabolism [50]. Imposed electric fields can cause polarization of mouse blastomeres [51]. The anterior-posterior polarity [52] and dorsal-ventral polarity [53] in lower animal morphogenesis can be reversed when the polarity of the imposed external electric field is opposite to that of the intrinsic bioelectric field.
4.3.3

Organizing Centers Have High Electric Conductance

	In development, the fate of a larger region is frequently controlled by a small group of cells which is termed an organizing center [54]. Organizing centers are the high electric conductance points on the body surface 140). The amphibian blastopore, a classic organizing center, has high electric conductance and current density [551. Similar phenomena have also been observed in higher vertebrates 156). The high conductance phenomenon is further supported by the finding of high density of gap junctions at the sites of organizing centers [57-60). At the macroscopic level, organiz ing centers are singular points in the morphogen gradient and electromagnetic field [40]. The electric potential gradient and chemical morphogen gradient are likely to enhance each other, as morphogens are usually charged molecules or ions and can form a more stable gradient over long range guided by electric field than by reactiondiffusion alone. The effect of morphogens on ion channels and pumps can modify the electric field. Disruption of the intrinsic electric field at the organizing center can cause malformation [55]. A change of electric activity at the organizing centers correlates with signal transduction and can precede morphologic change 161, 62]. For example, an outward current can be detected at the site of a future limb bud (an organizing center) in amphibians several days before the first cell growth [63].
	Fig. 1. Illustration of singular points and separatrices (modified from Fig. 2.1 11 171 (courtesy of John Wiley and Sons)) This also approximates the pattern of acupuncture points and meridians - the singular points and separatrices of electromagnetic field on the body surface
  	Fig. 2. Ionic currents traversing an embryo 11181 (courtesy of John Wiley and Sons) The blastopore, a classic organizing center, has high electric conductance and current density. A steady blastopore current persists after early embryogenesis. The electric fields polarize the embryo and serve as cues for morphogenesis. These results confirmed earlier predictions [1161
  4.3.4

Acupuncture Points - Organizing Centers

	Both acupuncture points and organizing centers have high electric conductance, current density, high density of gap junctions, and can be activated by nonspecific stimuli. A therapeutic effect of acupuncture can be achieved by a variety of stimuli 110, 64], including electricity, needling, temperature variation, laser [65], and pressure. Similarly, morphogenesis of organizing centers can be induced by various stimuli such as mechanical injury and injection of nonspecific chemicals [54, 66].
	Based on the phase gradient model in developmental biology 140, 67), many organizing centers are expected to be at the extreme points of curvature on the body surface, such as the locally most convex points (e.g., the apical ectodermal ridge and other growth tips) or concave points (e.g., the zone of polarizing activity). Similarly, almost all the extreme points of the body surface curvature are acupuncture points. For example, the convex points include EX-UE1I Shixuan, EX-LE12 Qiduan, St.17 Ruzhong, St.42 Chongyang, St.45 Lidui, SP.1 Yinbai, SP.10 Xuehai, GV25 Suliao, and more. The concave points include CV17 Danzhong, K1.1 Yongquan, SI.19 Tinggong, GB.20 Fengchi, BL.40 Weizhong, HT.1 Jiquan, BL.1 Jingming, CV8 Shenque, among others. These similarities between acupuncture points and organizing centers suggest that acupuncture points originate from organizing centers.
4.3.5

Why Do Auricles Have the Highest Density of Acupuncture Points?

	The distribution of acupuncture points and organizing centers is closely related to the morphology of the organism. For example, the auricle, which has the most complex surface morphology, also has the highest density of acupuncture points. According to the WHO, 43 auricular points have proven therapeutic value [ 11 ] and comprise 10 % of the acupuncture points of the whole body. Although an auricle has no important nerves or blood vessels and no significant physiological function other than sound collection, auricular morphology is one of the most sensitive indicators of malformations in other organs. Auricular malformation has been observed in Turner's syndrome, Potter's syndrome, Treacher-Collins syndrome, Patau's syndrome, Edwards' syndrome, Noonan's syndrome, maternal diabetes, atherosclerosis [68], Goldenhar's syndrome, Beckwith's syndrome, DiGeorge syndrome, cri du chat syndrome, and fragile X syndrome. It is recommended in a standard textbook of pediatrics that any auricular anomaly should initiate a search for malformations in other parts of the body [69].
4.3.6

Meridian-Separatrix Boundary

	At early stages of embryogenesis, gap junction-mediated cell-to-cell communication is usually diffusely distributed, which results in the entire embryo becoming linked as a syncytium. As development progresses, gap junctions become restricted at discrete boundaries, leading to the subdivision of the embryo into communication compartment domains [70]. These high conductance boundaries or separatrices are also major pathways of bioelectric currents and likely to be the precursors of meridians. Separatrices can be folds on the surface or boundaries between different structures [40, 711. It was proposed that interconnected cells in the meridian system remain underdifferentiated and maintain their regulatory function in a partial embryonic state [20, 40]. Consistent with this theory, it has been observed that the most apical parts of folds remain undifferentiated in morphogenesis [72], as well as organizing centers such as the zone of polarizing activity [73] and the apical ectodermal ridge [74]. The separatrix attributes are consistent with the observation in the Inner Classic (Nei ling) that meridians are distributed along the boundaries between different muscles. For example, part of the lung meridian runs along the borders of the biceps and brachioradialis. Part of the pericardium meridian runs between the palmaris longus and flexor carpi radialis. Part of the gallbladder meridian runs between the sternocleidomastoid and trapezius. Trigger points also tend to be located at the free borders of muscles 1751. The governor vessel and the conception vessel are the axis of symmetry on the body surface. They form the boundaries between many different structures. They are also regarded as the convergence of all meridians in traditional acupuncture.
4.3.7

The Role of the Meridian System in Evolution and Physiology

	In ontogeny, the development of organizing centers in the growth control system precedes the development of the nervous system and other physiological systems. The formation and maintenance of all the physiological systems are directly dependent on the activity of the growth control system. Based on the morphogenetic singularity theory, the meridian system originates from a network of organizing centers. As the individual embryonic development recapitulates the evolution of the species, (ontogeny recapitulates phylogeny), the evolutionary origin of the meridian system is likely to have preceded all the other physiological systems, including the nervous, circulatory, and immune systems. Its genetic blueprint might have served as a template from which the newer systems evolved. Consequently, it overlaps and interacts with other systems but is not simply part of them. The growth control signal transduction is embedded in the activity of the function-based physiological systems. Many neural, circulatory, and immune processes are regulated through growth control mechanisms such as hypertrophy, hyperplasia, atrophy, apoptosis with shared messenger molecules and common signal transduction pathways involving growth control genes such as proto-oncogenes [76-80]. Acupuncture also induces the expression of protooncogene c-fos [81, 82]. Many "nonexcitable" cells have shown electrochemical oscillation, coupling, long range intercellular communication [62, 83, 84], and can participate in the meridian signal transduction
4.3.8

Unified Basis of the Meridian and Chakra Systems

	Based on the morphogenetic singularity theory, the distribution of the meridian system is related to both internal and external structures and not solely determined by nerves, muscles, or blood vessels. The distribution is a result of morphogenesis. Therefore, acupuncture points which are not at obvious extreme points of surface curvature or meridians which are not at obvious boundaries can be vestigial or more related to internal structures. The underdifferentiated, interconnected cellular network is not limited to the body surface. One type of least differentiated cell is the germ cell. The primary tumor distribution pattern of a certain cell type reflects the distribution of its normal counterpart. For example, the distribution of primary pheochromocytoma reflects the distribution of normal sympathetic ganglion cells. The germ cell tumors [85, 86] have a midline and para-axial distribution pattern which extends from the sacrococcygeal region, through the anterior mediastinum, tongue, and nasopharynx to the pineal gland. It appears to concentrate at seven locations: sacrococcygeal region, gonads, retroperitoneum, thymus [87], thyroid [88], suprasellar region, and pineal gland [89]. The pattern resembles the chakra system used in yoga and acupuncture 1901, suggesting the existence of underdifferentiated cells which may be highly interconnected in a normal state as part of the "inner meridian system" and provide important regulatory functions [91]. It is likely that there is a hierarchy in the degree of cell differentiation and function in the meridian system, with the germ cell system (major chakra system) as the least differentiated and constituting the central core of the regulatory system. The more superficial meridians and acupuncture points are more differentiated and lower in the hierarchy.
  	Fig. 3. just as the distribution of pheochromocytoma correlates with the distribution of sympathetic ganglions, the distribution of germ cell tumors correlates with undifferentiated cells in human body which are likely to be involved in the regulation of growth control and physiology as part of the "inner meridian system". This distribution also correlates well with the chakra system used in yoga and acupuncture, suggesting a unified structural basis for chakra system and meridian system. Figure modified from: Govan ADT, MacFarlane PS, Callander R et al (1995) Pathology illustrated, 4th edn. Churchill Livingstone, London, p 150 and from: Stux (1997) Basics of acupuncture, 4th edn. Springer, Berlin, p 287. Courtesy of Churchill Livingstone and Dr. Gabriel Stux
 4.3.9

Mechanism of Meridian System-Based Diagnosis and Therapy

	As the electric conductance of organizing centers varies with morphogenesis, the conductance of acupuncture points also varies and correlates with physiological change [13] and pathogenesis [92, 93]. The facts that the change in electric field precedes morphologic change [63] and that manipulation of the electric field can affect the change [94] may shed light on the diagnosis [93, 95] and treatment of many diseases. According to the morphogenetic singularity theory [40], the network of organizing centers retains its regulatory function through high levels of intercellular communication correlated with relatively low levels of cell differentiation during and after embryonic development. This prediction is consistent with the finding that underdif- ferentiation and high electric conductance persists at the organizing centers after early embryogenesis [96]. The organizing centers communicate with other parts of the body to maintain proper forms and functions. Gap junctional communication has been shown to play a crucial role in morphogenesis [97]. The gap junction genes can also behave as classical tumor suppressor genes in both culture and animal tests in restoring growth regulatory properties to metastatic cancer cells [98]. An anomaly inside the organizing center network may be detected by measuring the electric parameters of some points on its surface at the early signal transduction stage and treated by manipulation of the interconnected organizing centers.
	The activation of organizing centers is likely to be involved in the restoration of proper form and function in wound healing and stress response. Acupuncture can speed up the wound healing process [99] and cause an exaggerated systemic wound healing and stress response 1100, 101]. The response can include excessive release of endorphin, which stimulates epithelial cell growth [102] as well as analgesia. Other neurohumoral factors induced by acupuncture such as serotonin 11031 and ACTH [ 1041 also have effects on growth control [ 105].
	In acupuncture, the often nonspecific perturbation at singular points (acupuncture points) may not directly antagonize a pathological process but may indirectly adjust the process and restore normal function by activating the network of organizing centers in the organism. For example, acupuncture at ST36 suppresses hyperfunction and stimulates hypofunction of gut motility [106]. The activation of organizing centers to elicit a normalizing function as explained above is less likely to cause the side effects resulting from directly antagonizing a pathological process which often overlaps with other normal and beneficial physiological processes. Therefore, proper use of these meridian system-based techniques causes few side effects [ 107-110], as demonstrated in randomized controlled trials [3, 4].
	A principle in electroacupuncture is that positive (anode) pulse stimulation of a point inhibits its corresponding function while negative (cathode) pulse stimulation enhances that function [ 111 ]. This polarity effect is similar to the finding that cell growth is enhanced toward cathode and reduced toward anode [48, 49] and consistent with the theory that the mechanism underlying acupuncture overlaps with that of growth control.
4.4

Conclusions

	The morphogenetic singularity theory outlines the common ground shared by the meridian and chakra systems and modern science. It is compatible with the findings from neurohumoral studies. It explains several phenomena and puzzles in developmental biology and acupuncture research, including the distribution of the meridian and chakra systems and germ cell tumors, the nonspecific activation of acupuncture points and organizing centers, the high electric conductance of acupuncture points, the polarity effect and side effect profile of electroacupuncture, and the ontogeny, phylogeny, and physiological function of the meridian system. Most of these have not been explained by any neurohumoral theory. In several prospective blind trials [55, 57-59, 711, researchers unaware of the theory confirmed its corollary on the role of singularity and separatrix in morphogenesis and its predictions of the high electric conductance and high density of gap junctions at organizing centers such as blastopores and zones of polarizing activity.
	Techniques involving the stimulation of the meridian system such as acupuncture and qigong [112, 113] may activate the self-organizing system of an organism and improve its structure and function at a more fundamental level than symptomatic relief. Development of these techniques may enable the diagnosis and treatment of a pathologic process at the early signal transduction stage prior to the anatomical or morphological change.
4.5

Prospects

	The advances reviewed above have broad implications in biomedicine beyond acupuncture. The current stage of meridian system research is analogous to that of physics in the early nineteenth century - during the transition from Newtonian mechanics to electromagnetics. More spectacular advances similar to those of relativity and quantum physics may await in the twenty-first century and will depend on the further development of meridian "electromagnetics" Many other areas related to the meridian system such as psychophysiology, chronobiology [114], and pulse analysis [115] await more rigorous studies. Many details of the current theories remain to be clarified and tested.
	Besides neurohumoral studies, the following directions of research are likely to be important in further understanding acupuncture and the meridian system:
	1. Mapping of the meridian system and the dynamics of its electromagnetic field with high resolution techniques such as SQUID
	2. The relation between the physical parameters of the meridian system and various pathological or physiological changes, including changes during acupuncture and gigong practice
	3. Development of acupuncture-related techniques of early diagnosis and treatment and establishing their cost effectiveness
	4. Clarifying the role of the meridian system in morphogenesis and growth control
	5. Exploring cell differentiation and signal transduction in the meridian system
	6. Mapping the body surface curvature through embryonic development and study of its relation to the meridian system
	Acknowledgements. I thank Drs. David Diehl, James Gordon, Richard Hammerschlag, Magnus Lou, and San Wan for their help and Drs. Mesterton-Gibbons and Gabriel Stux for permission to use figures from their books.
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  CHAPTER 5

  Functional Magnetic Resonance Imaging of the Brain 
 in the Investigation of Acupuncture

Z.-H. Cho • C.-S. Na • E. K. Wang • S.-H. Lee • I.-K. Hong

5.1

Introduction

	Medical imaging techniques that allow noninvasive observation of the structure and function of the human brain have improved dramatically during the past few decades. The relatively poor resolution of the biohazardous two-dimensional x-ray technique has been effectively replaced by safer and far more sensitive optical scanning techniques, including x-ray computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI). These modern advances in brain imaging routinely provide critical diagnostic information in such conditions as stroke, multiple sclerosis, and Parkinson's disease as well as basic insights into how we experience, respond to, and even think about the world [2, 5-8, 12, 15, 18, 22-24, 27].
	The application of this state of the art medical technology to the low tech, millennia-old practice of acupuncture seems at first to represent scientific overkill. But several preliminary explorations in this "west meets east" field of inquiry have yielded extremely promising results. For example, just as brain imaging is used on acute ischemic stroke patients to assess the need for administering so-called clot busting drugs [21), CT scans also have been effectively used to predict which stroke patients are likely to benefit from acupuncture treatment [20). In addition, noninvasive imaging techniques have obvious potential for corroborating the brain pathways mediating acupuncture analgesia that have been identified in animals by microelectrode recordings, focal application of pharmacological agents, and ablation studies (see chapters 1.3).
	The present chapter will focus in detail on the recent use of functional magnetic resonance imaging (fMRI) to test oriental medical theory [9, 10]. These studies have detected activity in the visual and auditory lobes of the brain during needling of distal acupoints on the leg and foot that Oriental medicine selects for treating eye and ear dysfunctions.
5.2

Brain Imaging for Identifying Neural Correlates of Acupuncture Analgesia

	Several imaging techniques, including PET, its related procedure single photon emission computed tomography (SPECT), and fMRI are used to measure neural activity as reflected in the uptake of cerebral blood glucose or increased cerebral blood flow. (Unlike most other cells, neurons have little stored glucose and rely on uptake of blood glucose as well as blood oxygen to sustain their high levels of activity.) The first two of these techniques are based on the use of radioisotopes that undergo predictable and detectable decay that can be resolved to specific brain regions. In a pilot study of five chronic pain patients, SPECT was employed to examine patterns of cerebral blood flow in various brain regions before and after acupuncture treatment [ I I. The most striking finding was that four of the five patients had a marked left/right asymmetry in pretreatment blood flow in the thalamus, a major site in the neural integration of pain sensation. Following acupuncture treatment that resulted in all five patients reporting pain relief, the thalamic asymmetry was greatly reduced. Control subjects showed no blood flow asymmetries either before or after acupuncture.
	The main advantage of MRI (for anatomical imaging) and tMRI (for physiological imaging) is their production of images without the use of radioisotopes. Since neural activity is critically dependent on oxygen derived from cerebral blood supplies, fMRl is an extremely sensitive means of measuring deoxyhemoglohin, the paramagnetic, oxygen-depleted carrier molecule. (Oxyhemoglobin is, fortuitously, nonmagnetic.) Functional MRI has been widely used for mapping changes in brain activity in response to specific sensory stimuli, motor tasks, or cognitive challenges as well as for detecting brain hemorrhages associated with pathological conditions [7, 8, 18, 23, 271.
	Laboratories in Boston [ 16, 171 and Taiwan [33] have begun using IMRI to examine brain activity in response to needling at acupoints LI.4 and St.36 in normal subjects. Significantly greater levels of brain activity were detected during periods of acupoint stimulation than during periods of rest, shallow needling, or superficial pricking on the leg. A wide variety of brainstem, midbrain, and cerebral cortical structures showed reproducible patterns of increased or decreased activity; changes were especially related to structures associated with ascending nociceptive and descending antinociceptive pathways. Once stronger magnets become available, the activity patterns and the pathways they reflect will be identifiable with greater spatial and temporal resolution.
5.3

Functional Magnetic Resonance Imaging for Examining Correlations Between Brain Cortical Activity and Acupoint Function

	Several of the studies seeking anatomical bases for acupuncture points and meridians support the possibility that meridians, the classically defined "energy transporting channels," are largely related to peripheral nerves [3, 41. In fact, comparisons of acupoints with the peripheral nervous system given in many anatomical books [30] show that many acupoints correspond with the sites where small nerve bundles penetrate the fascia [ 141. According to recently published reports, as many as 300 acupoints are situated on or very close to nerves, while an almost equal number are on or very close to major blood vessels that are surrounded by small nerve bundles [3]. This study, which also confirms that the acupoints lie along the peripheral nerves, leads us to hypothesize that acupuncture signals are projected to the brain via the spinal cord and brainstem. Such signals could terminate in subcortical areas, while many are likely to reach the higher cortical areas, including the sensory cortex.
	Fig. I. Conceptual relationships in the brain, organs, and acupoints that can be examined by fMRI. These relationships suggest functional interactions between acupoints and the cortical areas related to disease treatment by each acupoint. As examples, cortical areas are indicated that may be activated by eye- or ear-related acupoints
  	Acupoint/brain cortex relationships have been described in the Oriental acupuncture literature [ 11, 19, 311 and observed by experienced acupuncturists. More specifically, it has been hypothesized that the disease treatment claimed for acupuncture points may have somatotopic or sensory-related cortical correspondence (Fig. 1). We became interested in experimental testing of this hypothesis using fMRI to monitor cerebral cortical activity in areas functionally related to sensory conditions classically treated by selected acupoints. For example, visual dysfunctions that are localized and treated by Western medicine at sites along the retina/optic-nerve/occipital-lobe axis can, according to Oriental medicine, often be diagnosed by alterations in radial pulses corresponding to the urinary bladder (UB) and gallbladder (GB) channels. Such conditions can be treated, in turn, by needling along these meridians at distal acupoints localized on specific aspects of a toe, foot, and lower leg [11, 19]. More specifically, the UB meridian starts at the inner canthus of the eye, has 67 acupoints along its route, and ends on the lateral side of the little toe, while the GB channel starts at the outer canthus of the eye, has 44 acupoints, and ends at the lateral side of the fourth toe. The fMRI technique can therefore be used to explore quantitative correlations between acupoint stimulation and activation of functional areas of the brain. If aspects of Oriental medicine theory not predicted by the biomedical view of the body can be validated, e.g., correlations between sites of acupuncture stimulation and cerebral cortical activity not linked by known neural pathways, then an expanded theory of physiology may be required to combine aspects of both the Oriental and allopathic medical models.
	To test our hypothesis that sensory-related acupoints have brain cortical correspondence, fMRI signals were sought in the visual cortex following needling of acupoints GB.37 (used to treat eye-related diseases such as itchiness or pain in the eyes, cataracts, night blindness, and optic atrophy) and in the auditory cortex following needling of GB.43 (known to be effective for treating ear-related diseases such as deafness and tinnitus). We examined brain activity associated with stimulation of both acupoints and compared the results to our initial findings with another eye related acupoint, UB.67 [9]. For each of these three acupoints, the disease-related information and the cortical area expected to be activated are listed in Table 1. Distal acupoints on the lower leg and foot were chosen for ease of access, since subjects undergoing fMRI have their head, torso, and upper legs inside the magnet.
	 SPECIAL_IMAGE-page0116_0000.svg-REPLACE_ME 
  	Fig. 2. Relation of acupoint stimulation and fMRI activity in visual cortex. a Two eye-related acupoints and a nonacupoint overlaid on the nervous system. b Activation maps of the brain due to (i) direct retinal stimulation by flashing light, (ii) acupuncture stimulation of U6.67, (iii) acupuncture stimulation of GB.37, and (iv) acupuncture-like stimulation of a nonacupoint
 	In our initial studies, we tested whether needling of UB.67, an acupoint traditionally used for treating eye disorders, would produce brain activity in the visual cortex that is detectable by fMRI (Fig. 2). Surprisingly, needling of this point led to reproducible increases in blood flow, i.e., increased fMRI signals, in Brodmann's areas 17, 18, and 19 of the visual cortex (Fig. 2b, ii). The effects were comparable to the changes in blood flow in the visual cortex produced by stimulation of the retina with flashing light (Fig. 2b, i). Needling of proximal acupoints UB.66 and UB.65 on the same channel also produced visual cortex activation [9]. In contrast, no visual cortex activity was detectable following needling either nonacupoints on the foot 2-5 cm from the vision-related acupoints (Fig. 2b, iv) or acupoint Sp.1 on the large toe (Fig. 2a), which is irrelevant to the treatment of eye disorders. Of considerable interest, needling of GB.37, on a separate meridian but another of the most effective acupoints for the treatment of eye disorders (Fig. 3), again produced strong fMRI activity in the visual cortex (Fig. 2b, iii). Activation of the visual cortex following stimulation of GB.37 is also shown in a series of "optical slices" (Fig. 4).
  	Fig. 3. Acupuncture points overlaid on the peripheral nervous system as seen from anterior and posterior views
  	Fig.4. Activation results of acupuncture stimulation of vision-related acupoint GB.37 observed by fMRI optical slice imaging. Cortical activation is shown due to (a) direct retinal stimulation by flashing light and (b) needling of the vision-related acupoint GB.37
  	Fig. 5. Activation results of acupuncture stimulation of a hearing-related acupoint GB.43. Cortical activation due to (a) flashing light, (b) music, and (c) acupuncture at GB.43. In (c), note the primary activation of the auditory cortex similar to that detected during listening to music (b) but also the small activation in the visual cortex similar to that detected during flashing light (a). This, we believe, is a secondary effect, since GB.43 is also used for the treatment of eye-related disease (Table 1)
 	As a further exploration of this phenomenon in other cortical areas, activity in the auditory cortex detectable by fMRI was examined following stimulation of G13.43, one of the best-known acupoints for the treatment of ear-related disease (Fig. 5). Interestingly, needling this acupoint resulted in strong activation of the auditory cortex in a manner similar to direct auditory stimulation with music but also led to weak activation of the visual cortex. It has been empirically observed and noted in acupuncture texts that some acupoints are relatively specific while others have more diverse functions. According to experienced acupuncturists, such primary and secondary responses may also be dependent on the health status of the patient.
5.4

Implications and Hypotheses

	Our results provide the first scientific evidence that acupuncture "signals" are projected to neocortical areas of the brain for central processing. These observations of the cortical projections of "signals" following stimulation of several acupoints strongly support the notion that many effects of acupuncture are mediated through the central nervous system. This concept of CNS involvement is supported by a considerable body of experimental evidence in the area of acupuncture analgesia, where correlations have been observed between acupoint stimulation, analgesia onset, and release of a variety of neurotransmitters, endogenous opioids, and hormones in the brain, spinal cord, and peripheral circulation 111, 13, 25, 26, 32] (see chapters 1.3).
	Projections to the brain's sensory cortices and the eventual effect on diseased organs by the brain's higher centers may occur in concert with other functional centers in the body. The well-known homunculus of the human cortex illustrates just such a somatotopic possibility [28, 29]. To gain additional support for the theory of a CNS-mediated mechanism relating acupoints with disease sites as proposed from our preliminary findings, it seems necessary to study effects of many more prominent acupoints related to somatosensory and visceral organ systems. However, current observations may lead to some useful new hypotheses.
	For example, we may hypothesize that stimulation of a specific acupoint delivers information to the corresponding cortical area(s), enabling the higher centers of the brain to make necessary decisions to regulate activities controlled by the endocrine and autonomic nervous systems. For this to occur, we believe that the hypothalamus and the amygdala play a key role, both in mediating the sensory input to the prefrontal cortex by integrating limbic information and in retrieving it from the prefrontal cortex. Information thus received from the amygdala would then be acted upon by the hypothalamus. The hypothalamus has unusually rich connections (both afferent and efferent) to many higher cortical areas such as the prefrontal cortex (both directly and via the amygdala), the limbic areas, and the brainstem and spinal cord.
	One of the hypotheses postulated to explain acupuncture phenomena in terms of these neurobiological mechanisms is known as the beta-endorphin theory, which is presented schematically in Fig. 6 [13, 25, 32]. It is interesting to note that, in this model, the hypothalamus interacts with the higher cortical areas, especially the prefrontal cortex. A further extension of this acupuncture therapy model depicts the sen sory hierarchy coupled to the motor hierarchy via the limbic-hypothalamus or great limbic system (Fig. 7). In this schema, the final executive center is the hypothalamus where three survival-related systems involving endocrine, autonomic (ANS), and neuromodulatory functions are controlled.
	The thrust of the present findings is that acupuncture stimulation is projected to higher brain areas such as the visual and auditory cortices. It is postulated that information is relayed from these sites to other key processing areas including the prefrontal cortex and limbic system. It is likely that acupuncture signals projected to these higher cortical areas will induce pain modulation as previously postulated but may also affect other survival-related functions. These latter mechanisms may shed light on what has been a mystery for many acupuncture investigators, namely how acupuncture treats various diseases beyond the level of pain relief. In Fig. 8, an overall acupuncture disease treatment model is shown that contains but goes beyond current endorphin-mediated theories of pain control.
  	Fig.6. A pain relief hypothesis involving higher cortical areas. In this example, the hypothalamus and other higher cortical areas are involved in secretion of beta-endorphin as well as other opioids and neurotransmitters. This hypothesis suggests involvement of higher cortical areas such as the sensory cortex as well as the frontal cortex, especially the prefrontal cortex and the limbic areas I11 ]
 	We may conclude that clues to the basic mechanisms underlying the several thousand-year-old practice of acupuncture will be revealed through modern scientific imaging techniques such as PET and fMRI. The careful and systematic examination of the hundreds of currently known acupoints and the mapping of corresponding cortical activation may well reveal evidence of homeostatic regulatory mechanisms not yet understood by Western physiology and medicine. Furthermore, future research with stronger magnetic fields will allow greater temporal and spatial resolution so that more subtle acupuncture signals can be detected. Such research will also contribute significantly to creating more accurate and reliable treatment for the millions of patients who may benefit from alternative medical therapies such as acupuncture.
	Acknowledgements. The present work is the product of many coworkers and their generous support. We are especially indebted to Drs. Heoung-Keun Kang and Gwang- Wu Chung in the Department of Diagnostic Radiology of Chun Nam University School of Medicine, Kyangju, Korea for their support of our use of MRI scanners.
  	Fig. 7. Functional brain hierarchies of motor and sensory functions. To illustrate the possible involvement of the acupuncture disease treatment effect, the limbic system is inserted as a mediator between the prefrontal cortex and the multimodal sensory association cortex. Here we hypothesize that acupuncture signals are projected to the sensory cortex and that the hypothalamus controls three major survival-related systems: endocrine, ANS, and diffuse modulatory neurochemical functions
  	Fig. 8. Model of the therapeutic effects of acupuncture analgesia. As diagrammed in this model, the importance of cortical projection of acupuncture stimuli is the possibility it presents of integrating the endocrine, ANS, and neurochemical regulation by the hypothalamus with activities of other higher cortical centers such as the prefrontal cortex and the limbic system
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  CHAPTER 6

  Neurophysiological Basis of Auricular Acupuncture

T. Oleson

6.1

Introduction

	Of all the areas of acupuncture, one of the most challenging aspects for acceptance by Western trained scientists is the use of acupuncture points on body organs that are distant from the site of pathology. One such remote system is the application of needles, electrical stimulation, or applied pressure to specific regions of the external ear or auricle. Western scientists are particularly skeptical of the concept that the organization of auricular acupoints can be seen as configured like an inverted fetus. Upper regions of the external ear are used to alleviate conditions in the legs and feet, middle regions represent chest problems and back pain, while lower regions relieve headaches and neurological disorders. The purpose of this chapter is to review the history, theories, clinical studies, and neurophysiological research which has examined this field of auricular acupuncture. There is growing scientific evidence which not only supports its use as an effective clinical modality but also suggests that acupuncture points on the external ear have specific connections to the central nervous system, which then affect reflexes in other parts of the body.
6.2

Somatotopic Organization of Auricular Acupuncture Points

	Classic acupuncture theory attributes chronic pain and pathological disease to the blockage of energy flow along acupuncture meridians, invisible lines of force extending over the surface of the body. Ancient Oriental medical texts described direct energy connections between the yang acupuncture meridians on the body and acupuncture points on the external ear [22]. However, the Chinese revised their use of auricular acupuncture in 1958 after they learned of the inverted fetus map of the ear first described by Dr. Paul Nogier of Lyon, France (Fig. 1). While familiar with an energy perspective of the human body [17], Nogier's theory for the spatial arrangement found on the external ear [34] was based primarily on the proposition that there are neurophysiological connections between auricular reflex points and the central nervous system. The somatotopic pattern said to exist on the external ear is configured in a manner similar to the neurological homunculus demonstrated for the human cerebral cortex [43]. Neurophysiological research has not yet revealed a connection between Nogier's auricular map and the somatotopically organized neurons in the brain, but this remains an exciting area for future investigations.
	Fig. 1. Inverted fetus map represented on the auricle of the external ear
  	Nogier suggested that there are three different zones on the external ear which are related to different types of neural innervation and different categories of embryological tissue 135]. A picture of the external ear identifying the nomenclature for different anatomical regions of the auricle is shown in Fig. 2, whereas the specific functional zones of the ear are represented in Fig. 3. The central concha of the ear is innervated by the vagus nerve and serves as the region for autonomic regulation of pain and pathology originating from internal organs. The surrounding antihelix and antitragus ridges of the ear represent somatic nerve processing of myofascial pain, backaches, and headaches. The outer helix tail and earlobe represent the spinal cord and brain regions which affect neuropathic pain such as peripheral neuropathies and trigeminal neuralgia. The body organs represented on the external ear can be viewed as three concentric rings: the embryologically based endodermal organs are "found" at the center of the ear, the mesodermal tissue that becomes the somatic musculature is represented on the middle ridges of the auricle, and the ectodermal skin and nervous system tissue are found on the outer ridges. Each of these three auricular regions depicts body orientation in an inverted somatotopic pattern. Higher organs of the actual lungs, shoulder, or cerebral cortex are represented on lower areas of the auricle, whereas lower organs of the actual intestines, leg, or lumbar spinal cord are represented farther up on the auricle (Fig.4).
	It has been proposed by Oleson 136] that the relief of pain by auricular acupuncture can be best understood by the theory of stimulation-produced analgesia. Liebeskind et al. 1301 developed this theory to account for the pain relieving effects following electrical stimulation of neurons in the brain. In addition to the classically known, ascending pain sensation pathway, there is a descending pain inhibitory pathway. The latter travels from the brainstem down the spinal cord; it then activates pain suppressive cells in the dorsal horn of the spinal cord. In their gate control theory of pain, Melzack and Wall [33] proposed that there was an inhibition of input from nociceptive neurons by input from tactile neurons interacting through spinal cord interneurons. They further allowed that supraspinal gates in the brain could produce descending inhibition of the ascending pain messages.
	Fig. 2. Nomenclature for anatomical regions of the external ear
  	Fig. 3. Functional zones represented on the auricle. An endodermal region is shown in the central concha of the ear, representing vagus nerve control of autonomic disorders. A mesodermal region is shown in the middle ridges of the antihelix and antitragus, representing somatic nerve control of myofascial pain. An ectodermal region is shown in the outer helix and lobe of the auricle, representing central nervous system regulation of neuropathic pain
  	Fig. 4. An inverted somatotopic representation on the auricle is shown, indicating that the feet and legs are represented toward the top of the external ear and the head is represented toward the lower antitragus and lobe of the auricle, with the rest of the body in between
  	Basbaum and Fields [4]showed that lesions in the descending, dorsolateral funicular tract in the spinal cord blocked behavioral analgesia from deep brain stimulation. There are both descending pain facilitation and descending pain inhibition systems in the central nervous system. Destruction of descending, serotonergic, raphe pathways and descending, noradrenergic, locus coeruleus pathways both lead to an increase in the activity of nociceptive spinal neurons, as measured by increased fos proteins, indicating that the pain inhibitory pathway has been damaged 1551. Conversely, destruction of descending reticular gigantocellular pathways leads to a decrease in the activity of nociceptive spinal neurons, suggesting that the pain facilitation system was altered by the spinal lesion.
	Liebeskind et al. [30] found that the same areas of the brain which can perceive pain messages are also involved in the inhibition of pain signals. Deep brain stimulation suppressed nociceptive spinal neurons but not sensory neurons, which only responded to light tactile stimuli. Multiple unit responses in the midbrain and the thalamus of rats evoked by noxious stimuli are also attenuated by the activation of the periaqueductal gray and raphe nuclei of the rat brainstem, whereas neural responses evoked by non-noxious air puffs remained the same after brain stimulation [40]. The most potent area for obtaining stimulation-produced analgesia in rats was the midbrain periayueductal gray, a region containing neurons specifically responsive to noxious stimuli. Research in primates [37] has shown that deep brain stimulation in the subcortical thalamus is a more potent site for obtaining stimulation-produced analgesia in higher species. Examination of stimulation-produced analgesia in human patients has shown similar findings [19]. Human research has confirmed that nociceptive pain messages activate positron emission tomography (PET) scan activity in the periaqueductal gray, hypothalamus, somatosensory cortex, and prefrontal cortex [21], which includes the same brainstem and thalamic areas that are able to suppress pain messages. While direct connections between auricular acupuncture points and these antinociceptive brain pathways have not yet been investigated, neurophysiological investigations of body acupuncture points suggest that the regions of the brain related to pain inhibition are also affected by the stimulation of acupoints.
6.3

Neurophysiological Theories of Acupuncture and Microacupuncture Systems

	According to Ralph Alan Dale [12], the holographic homunculus pattern shown on the external ear is one of several microacupuncture systems that connect peripheral regions of the body to the central nervous system. Dale suggests that the ear points have remote reflex connections to other parts of the body through neuronal pathways in the central nervous system. Dale has proposed that there are both organocutaneous reflexes, which allow the microsystem to reveal underlying body pathology, and cutaneo-organic reflexes, which enable microacupuncture stimulation to heal the pathological condition. Foot reflexology and hand and scalp acupuncture are other examples of such microacupuncture systems, each serving as peripheral terminals in the body that connect to a central brain computer [36].
	Tsun-nin Lee [28, 29] hypothesized a thalamic neuron model to account for reflex connections between acupuncture points and the brain. According to this view, pathological changes in peripheral tissue will eventually lead to dysfunctional neural firing patterns in the correspondent neural microcircuits in the brain and spinal cord. The organization of the connections between peripheral nerves and the CNS is controlled by sites in the sensory thalamus that are arranged like a homunculus. The CNS institutes corrective measures intended to normalize the disordered neural circuits, but strong environmental stressors or intense emotions may cause the CNS circuitry to malfunction. If the neurophysiological programs in the neural circuits are impaired, the peripheral disease may remain chronic. Pain and disease are thus attributed to learned, maladaptive programming of these neural circuits. Stimulation of acupuncture points on the body or the ear can serve to induce reorganization of these pathological brain pathways. The spatial arrangement of these neuronal chains within the thalamic homunculus is said to account for the arrangement of acupuncture meridians in the periphery. The invisible meridians which purportedly run over the surface of the body may actually be due to nerve pathways projected onto neuronal chains in the thalamus. The auricular acupuncture system is more noticeably arranged in a somatotopic pattern on the auricular skin surface.
	There have been four main questions in acupuncture research designed to examine these neurophysiological theories:
	1. Can the existence of auricular and body acupuncture reflex points be substantiated by electrophysiological measures?
	2. Are the areas of the brain associated with stimulation-produced analgesia also affected by the stimulation of acupuncture points?
	3. Do changes in the natural opiates, the endorphins and enkephalins, reliably account for the pain relieving effects of auriculotherapy and body acupuncture?
	4. Is there evidence that the somatotopic pattern described for the auricle is specifically associated with changes in neural activity in different parts of the brain?
6.4

Electrodermal Determination of Acupuncture Points

	A principal area of interest has been the examination of whether the bioelectric properties of auricular acupuncture points correlate with the presence of disease or dysfunction of the corresponding area of the body. The first double blind assessment to validate scientifically the somatotopic pattern of reflex points on the auricle was conducted by Oleson et al. [39]. Forty patients with specific musculoskeletal pain problems were first evaluated by a doctor or nurse to determine the exact body location of their physical pain. They were then draped with a sheet to cover their body so that only their external ear was exposed to view. Crutches and braces were removed from the room in order to prevent any clues as to the nature of their condition. A second medical doctor with extensive training in auricular acupuncture procedures then examined each patient's ear. This second doctor had no prior knowledge of the subject's previously established medical diagnosis and was not allowed to interact verbally with the patient. Auricular diagnosis was determined by numerically rated levels of tenderness to a palpating probe and by the quantified electrical conductivity of the skin. Specific areas of the auricle which corresponded to different musculoskeletal regions of the body were examined. There was a positive correspondence between auricular points identified as reactive, both tender to palpation and exhibiting at least 50 ftA of electrical conductivity, and the parts of the body where there was musculoskeletal pain. Nonreactive ear points corresponded to parts of the body from which there was no reported pain. The statistically significant overall correct detection rate was 75.2 %. When the pain was located on only one side of the body, electrical conductivity was significantly greater at the somatotopic ear point on the ipsilateral ear than at the corresponding area of the contralateral ear. These results supported the concept that specific areas of the ear are related to specific areas of the body.
	Double blind assessment of auricular points that are related to heart disorders was conducted by Saku et al. in Japan 1481. Reactive electropermeable points on the ear were defined as auricular skin areas with electrical current conductance greater than 50 µA, indicating relatively low skin resistance. There was a significantly higher frequency of reactive ear points at the Chinese heart points in the inferior concha (84 %) and on the tragus (59%) for patients with myocardial infarctions and angina pain than for a control group of healthy subjects (11 %). There was no difference between the coronary heart disease group and the control group in the electrical reactivity of auricular points that did not represent the heart. The frequency of electropermeable auricular points for the kidney (5 %), stomach (6 %), liver (10 %), elbow (I I %), or eye (3 %), was the same for coronary patients as for individuals without coronary problems. Whereas Oleson et al. [391 had supported the concept that Nogier's mesodermal antihelix zone on the ear corresponds to musculoskeletal pain, Saku et al. established that specific points on the endodermal concha region of the ear were associated with a visceral condition such as heart disease.
	Quantified examinations of the electrical properties of the skin have provided the most objective demonstration of the scientific validity of acupuncture points [5, 6, 38, 45]. Observations that acupuncture points exhibit higher levels of skin conductance or lower levels of skin resistance than surrounding skin surface areas were first reported in the 1950s by Nakatani in Japan and Niboyet in France. In the 1970s, Mat- sumoto showed that 80 % of acupuncture points could be detected as low resistance points. The electrical resistance of acupuncture points was found to range from 100 to 900 kOhm, whereas the electrical resistance of nonacupuncture points ranged from 1100 to 11,700 kOhm. Taking great care to control for electrical resistance variance due to pressure on the skin by the detecting probe, Reichmanis, Becker, and Marino [45] systematically verified that the electrodermal resistance at acupuncture points is significantly lower than in surrounding tissue. In addition, meridian acupuncture points exhibit even lower electrical resistance when there is pathology in the organ they represent. For instance, electrodermal resistance on the lung meridian is lower when one has a respiratory disorder, whereas skin resistance on the liver meridian is lower when one has a liver disorder. The normal, bilateral symmetry of the electrical resistance of acupuncture points is disturbed when there is unilateral pathology in the body. Those acupuncture points that are ipsilateral to the site of body discomfort exhibit a lower electrical resistance than the corresponding meridian point on the contralateral side of the body. Oleson et al. [39] found that auricular points showed a similar ipsilateral pattern.
	Xianglong et al. of China examined 68 healthy adults for computerized plotting of low skin resistance points [58]. A silver electrode was continuously moved over a whole area of body surface while a reference electrode was fastened to the hand. Starting from the distal ends of the four limbs, investigators moved the electrode along the known meridians. The resistance of low skin impedance points (LSIP) was approximately 50 kOhm, whereas the impedance at non-LSIP was typically 500 kOhm. The LSIP were distributed over the body, predominantly along the 14 classic acupuncture meridian channels. A total of 64 % of LSIP were located exactly on a channel and 83.3 % were located within 3 mm of a channel. In only a few cases could individual LSIP be found in nonchannel areas. There was not an uninterrupted, continuous line of low skin impedance, but a series of electroactive points distributed along the meridian channel. There was no marked natural fluctuation of skin impedance, and the distribution of LSIP was considerably stable and repeatable from one day to the next.
	Chiou et al. [8] examined the topography of low skin resistance points (LSRP) in rats. The moveable search electrode was a polished acupuncture needle applied with uniform pressure which did not pierce the skin, and the reference electrode was a needle inserted into the tail. Specific LSRP loci were distributed symmetrically and bilaterally over the shaved skin of the animal's ventral, dorsal, and lateral surfaces. The arrangement of LSRP corresponded to the acupuncture meridians found in humans and were hypothesized to represent zones of autonomic concentration, the higher electrical conductivity being due to higher neural and vascular elements beneath the points. The LSRP gradually disappeared 30 minutes after the animal's death.
	Skin and muscle tissue samples were obtained by Chan et al. [7] from four anesthetized dogs. Acupuncture points, defined by regions of low skin resistance, were compared to control points exhibiting less conductivity. The points were marked for later histological examination. Concentration of substance P was significantly higher at skin acupuncture points (3.33 ng/g) than at control skin points (2.63 ng/g) that did not exhibit low skin resistance. Its concentration was also significantly higher in skin tissue samples (3.33 ng/g) than in the deeper, muscle tissue samples (1.81 ng/g). Substance P is known to be a spinal neurotransmitter found in nociceptive, afferent Cfibers. It plays a role in pain transmission, stimulates contractility of autonomic smooth muscle, induces subcutaneous liberation of histamine, causes peripheral vasodilation, and leads to hypersensitivity of sensory neurons. This neurotransmitter seems to activate a somatoautonomic reflex that could account for the clinical observations of specific acupuncture points that are both electrically active and tender to palpation.
	Experimentally induced changes in auricular reflex points in rats were examined by Kawakita et al. [25]. The submucosal tissue of the stomach of anesthetized rats was exposed and acetic acid or saline was injected into the stomach tissue. Skin impedance of the auricular skin was measured by constant voltage square wave pulses. A silver metal ball, the search electrode, was moved over the surface of the rat's ear and a needle inserted into subcutaneous tissue to serve as the reference electrode. Injection of acetic acid led to the gradual development of lowered skin resistance points on central regions of the rats' ears, auricular areas corresponding to the gastrointestinal region of human ears. In normal rats and in experimental rats before the surgical operation, low impedance points were rarely detected on the auricular skin. After experimentally induced peritonitis, there was a significant increase in low impedance points (0-100kOhm) and moderate impedance points (100-500kOhni), but a decrease in high impedance points (> 500 kOhm). These results demonstrated a reduction in the electrodermal resistance response to experimentally induced irritation of the internal organ related to that auricular point. Histological investigation could not prove the existence of sweat glands in the rat auricular skin. The authors suggested that the low impedance points are in fact related to sympathetic control of blood vessels. It would have been intriguing if the investigators had conducted further evaluation of the auricular low resistance sites for concentrations of substance P, as Chan et al. had done for body acupoints [7]. Kawakita's study provides objective support for the organocutaneous reflexes described by Dale ([12], wherein low resistance auricular acupuncture points appear in response to pathology of the corresponding internal organ.
6.5

Changes in Brain Activity Following Auricular Acupuncture for Obesity

	An intriguing use of auricular acupuncture has been its clinical application for weight control. Sun and Xu [54] treated overweight patients with otoacupoint stimulation, another term for ear acupressure. All patients were also given body acupuncture for the 3-month period of the study. The acupuncture group consisted of 110 patients diagnosed with at least 20 % more than ideal weight. They were compared to 51 obesity patients in a control group given an oral medication for weight control. An electrical point finder was used to determine the following auricular points: mouth, esophagus, stomach, abdomen, hunger, shen men, lung, and endocrine. Pressure pel lets made from vaccaria seeds were applied to the appropriate points of both ears. The body acupuncture points needled included St.25, St.36, St.40, Sp.6, and Pe.6. The average 5 kg reduction in body weight by the acupuncture group was significantly greater than the average 2 kg loss shown by the control group. The percentage of body fat was reduced by 3 % in the acupuncture group and by 1.54 % in the control group, while the triglyceride blood lipid levels were diminished 67 units in the acupuncture group and 38 units in the control group.
	A randomized controlled trial by Richards and Marley [47] found that weight loss was significantly greater for women in an auricular acupuncture group than in a control group. Women in the auricular group were given surface electrical stimulation to the ear acupoints for stomach and shen men, whereas women in the control group were given transcutaneous electrical stimulation to the first joint of the thumb. Auricular acupuncture was theorized to suppress appetite by stimulating the auricular branch of the vagus nerve and raising serotonin levels, both of which increase smooth muscle tone in the gastric wall. Rather than examine changes in weight measurements, Choy and Eidenschenk examined the effect of tragus clips on gastric peristalsis in 13 volunteers [9]. The duration of single peristaltic waves was measured before and after the application of ear clips to the tragus. The frequency of peristalsis was reduced by one-third with clips on the ear and returned to normal with the clips off. The ear clips were said to produce inhibition of vagus nerve activity, leading to a delay of gastric emptying, which would then lead to a sense of fullness and early satiety. These obesity studies on human subjects have received potential validation from neurophysiological research in animals.
	The areas of the brain classically related to weight control include two regions of the hypothalamus. The ventromedial hypothalamus (VMH) has been referred to as a satiety center; when the VMH is lesioned, animals fail to restrict their food intake. In contrast, the lateral hypothalamus (LH) is referred to as a feeding center, since stimulation of the LH induces animals to start eating food. Asamoto and Takeshige [3] studied selective activation of the hypothalamic satiety center by auricular acupuncture in rats. Electrical stimulation of inner regions of the rat ear which correspond to auricular representation of the gastrointestinal tract produced evoked potentials in the ventromedial hypothalamus (VMH) satiety center but not in the lateral hypothalamic (LH) feeding center. Stimulation of more peripheral regions of the rat ear did not activate hypothalamic evoked potentials, indicating the selectivity of auricular acupoint stimulation. Only the somatotopic auricular areas near the region representing the stomach caused these specific brain responses. Acupuncture needles were subsequently placed into the same auricular sites as those that led to evoked potentials in the VMH. After 16 days, the body weights of rats in the auricular acupuncture group was significantly lower than in a control group of rats that were not needled. The same auricular acupuncture sites that led to hypothalamic activity associated with satiety led to behavioral changes in food intake. Moreover, auricular acupuncture had no effect on a different set of rats that received bilateral lesions of VMH. These results indicate a compelling connection between auricular acupuncture and a part of the brain associated with neurophysiological regulation of feeding behavior. The hypothalamus also regulates visceral activity affected by the autonomic vagus nerve.
	In support of this evoked potential research, Shiraishi et al. [49] recorded single unit, neuronal discharge rates in the ventromedial hypothalamus (VMH) and lateral hypothalamus (LH) of rats. The firing pattern of hypothalamic neurons was recorded in response to electrical stimulation of specific areas of the rats' ears. A particular focus was on stimulating low resistance regions of the interior concha of the ear, areas of the auricle innervated by the vagus nerve and corresponding to the stomach in human ear acupuncture charts. Auricular stimulation tended to facilitate neuronal discharges in the VMH and inhibit neural responses in the M. Out of 162 neurons recorded in the ventromedial hypothalamus, 44.4 % exhibited increased neuronal discharge rates in response to auricular stimulation, 3.7 % of VMH neurons exhibited decreased activity, and 51.9 % showed no change. Of 224 neurons recorded in the LH feeding center of 21 rats, 22.8 % were inhibited by auricular stimulation, 7.1 % were excited, and 70.1 % were unaffected. When the analysis was limited to 12 rats classified as responding behaviorally to auricular acupuncture stimulation, 49.5'%, of LH units were inhibited, 15.5 % were excited, and 35.0 % were unaffected by auricular stimulation. A different set of rats were given lesions of the ventromedial hypothalamus, which led to significant weight gain. In these hypothalamic obese rats, 53.2 % of I I I LH neurons were inhibited by auricular stimulation, 1.8 % showed increased activity, and 45 % were unchanged. These neurophysiological findings suggest that auricular acupuncture can selectively alter hypothalamic brain activity and is more likely to produce sensations of VMH satiety than reduction of LH appetite.
6.6

Reduction of Neurophysiological Nociceptive Responses by Acupuncture Stimulation

	A central focus of neurophysiological research on acupuncture treatment has been the assessment of changes in neural responses related to pain. As stated previously, deep brain stimulation of the periaqueductal gray leads to pain reduction in rats, cats, monkeys, and man [30], an analgesic effect which can be reversed by the opiate antagonist naloxone. Such stimulation-produced analgesia by brain electrodes directly elevates endorphin levels in the CSF and blood plasma levels of animals [42] and human patients [2, 19].
	Pert et al. [441 showed that 7 Hz electrical auricular stimulation through needles inserted into the concha of the rat produced an elevation of the hot plate threshold which was reversed by naloxone. The behavioral analgesia to auricular electroacupuncture was accompanied by a 60% increase in radioreceptor activity in CSF levels of endorphins, a level significantly greater than that found in a rat control group. Concomitant with these CSF changes, auricular electroacupuncture produced depletion in beta-endorphin radioreceptor activity in the ventromedial hypothalamus and the medial thalamus but not in the periaqueductal gray. Supportive findings in human back pain patients were obtained by Clement-Jones et al. [ 11 J. Low frequency electrical stimulation of the concha led to relief of pain within 20 minutes of the onset of electroacupuncture and an accompanying elevation of CSF beta-endorphin activity in all ten subjects. Abbate et al. [ 1 ] examined endorphin levels in 12 patients undergoing thoracic surgery. Six were given 50 % nitrous oxide combined with 50 Hz auricular electroacupuncture while six control patients underwent their surgery with 70% nitrous oxide but no acupuncture. The auricular acupuncture patients not only needed less nitrous oxide than the controls, but the ear acupuncture also led to a significant increase in beta-endorphin immunoreactivity.
	A review of the neurophysiological literature by Kho and Robertson [26] provides empirical support for the role of the thalamus in acupuncture analgesia. Afferent acupuncture impulses are thought to activate nociceptive inhibitory pathways and selectively alter specific neurotransmitters. Gao et al. [ 16] found that after giving 4 Hz electroacupuncture of St.36, the autoradiographic mu-enkephalin receptor binding sites were significantly increased in the following brain areas of rats: caudate, septal nucleus, medial preoptic, amygdala, periaqueductal gray, nucleus raphe magnus, cervical spinal cord, and lumbar spinal cord dorsal horn.
	Kalyuzhnyi et al. [24] applied 15 Hz electrostimulation to the auricular lobes of rabbits in an area corresponding to the jaw and teeth in humans. They measured behavioral reflexes and cortical somatosensory evoked potentials in response to tooth pulp stimulation. Auricular electroacupuncture produced a significant decrease in behavioral reflexes and in cortical evoked potentials following electrical stimulation of the teeth. For most animals, the suppression of behavioral and neurophysiological effects was abolished by injection of the opiate antagonist naloxone, suggesting endorphinergic mechanisms. In a few rabbits, however, auriculoacupuncture stimulation did not induce this naloxone reversible effect, and naloxone injections themselves led to an analgesic effect. The authors suggested that this paradoxical effect could be explained by an inhibition of an antiopioid substance in select individuals. Fedoseeva et al. [ 15] also examined electrical stimulation of auricular acupuncture at earlobe points in rabbits, the auricular area that corresponds to the trigeminal nerve. Auricular electroacupuncture led to a reduction of the amplitude of cortical somatosensory potentials evoked by tooth pulp stimulation. Intravenous injection of the opiate antagonist naloxone diminished the analgesic effect of auricular electroacupuncture at 15 Hz stimulation frequencies but not at 100 Hz stimulation. Conversely, injection of saralasin, an antagonist of angiotensin II, blocked the analgesic effect of 100 Hz auricular acupuncture but not 15 Hz stimulation. The amplitude of cortical potentials evoked by electrical stimulation of the hind limb was not attenuated by stimulation of the auricular area for the trigeminal nerve.
	There is a larger body of research which has examined changes in the brain following body acupuncture, often relying on acupuncture needling of the presumed location in animals of St.36 on the lower leg known as zusanli, or LI.4 known as either hegu or hoku. Stimulation of body acupuncture points leads to elevation of pain thresholds in animals [41] and in man [32]. Brain research by Li et al. [31] found that electrical stimulation of the reticularis gigantocellularis nucleus (RGC) of rats could enhance acupuncture analgesia on the tail flick test produced by electroacupuncture at St.36. Lesions of reticularis gigantocellularis nucleus could reduce acupuncture analgesia, while microinjections of naloxone into this same brainstem nucleus could partially block acupuncture analgesia. Radioimmunoassays for opioid peptides released from the RGC revealed that leu-enkephalin and beta-endorphin levels increased after acupuncture stimulation, whereas opioid peptide levels remained stable in a control group. Similar research by Wu et al. [57] showed that electroacupuncture applied to LI.4 led to an increase in pain threshold and in leu-enkephalin and beta-endorphin levels in the preoptic area of rabbits. Norepinephrine release in the preoptic area was decreased by acupuncture and reversed by perfusion with nalox one. Electroacupuncture was also shown to reduce the evoked response to nociceptive input by excitatory preoptic neurons, an effect which was also reversed by naloxone microinjections into the preoptic area.
	Renhua et al. [46] examined 24 rabbits anesthetized with urethane and given bilateral stimulation of acupuncture point St.36. Acupuncture was applied with either manual twirling of needles or with electroacupuncture. The volume of microcirculatory blood flow in the cerebral pia mater increased 62 % after electroacupuncture and increased 18 % after manual acupuncture. Sonoda et al. [52] have shown that activation of the brainstem periaqueductal gray can lead to inhibition of palmar galvanic skin reflexes, demonstrating the effect of the pain inhibition pathway on autonomic arousal. This inhibition is eliminated by intravenous administration of naloxone, suggesting that the endorphinergic pathways play a role in acupuncture-induced reductions in autonomic electrodermal activity and autonomic elevations of blood circulation.
	Simmons and Oleson [50] examined naloxone reversibility of auricular acupuncture analgesia to acute induced pain. All 40 volunteers were assessed for tooth pain threshold by a dental pulp tester. Dental pain levels were determined before and after auriculotherapy and again after double blind injection of naloxone or placebo. Subjects were assigned to one of four groups: true auricular electrical stimulation (AES) followed by an injection of naloxone, true AES followed by an injection of saline, placebo stimulation of the auricle followed by an injection of naloxone, or placebo stimulation of the auricle followed by an injection of saline. Dental pain thresholds were significantly raised by AES conducted at auricular points appropriate for dental pain. Pain thresholds were not altered by sham stimulation at inappropriate auricular points. Naloxone produced a slight lowering of dental pain threshold in the subjects given true AES, whereas true AES subjects given saline showed a further rise in pain threshold. The minimal changes in dental pain threshold shown by the sham auriculotherapy group were not significantly affected by saline or naloxone. Both Sjolund and Eriksson 1511 and Simmons and Oleson noticed that pain threshold levels did not completely return to baseline after administration of naloxone, suggesting nonopioid as well as endorphinergic brain mechanisms.
	Hsieh compared manual stimulation of St.36 to 2 Hz electroacupuncture applied at the same point in 13 healthy male subjects [20]. Electrodermal skin responses were recorded from both palms to measure the autonomic arousal response to electric shock stimulation of the median nerve on the right wrist. Somatic cortex evoked potentials were recorded at the hand area of the left somatosensory cortex, consisting of short latency, negative wave potentials (N 13 and N 20), and a long latency, positive wave potential (P25). The amplitude of evoked electrodermal responses (EDR) was attenuated 50% by electroacupuncture and reduced 31 % by manual acupuncture. There were no differences in left and right electrodermal responses, indicating a generalized inhibition of the sympathetic nervous system response. The mean amplitude of the N 13 and N 20 wave somatosensory evoked potentials were unaffected by acupuncture, whereas the amplitude of P 25 waves was elevated 13 % by electroacupuncture and 6 % by manual acupuncture. These changes reflected an increase in cortical enhancement of peripheral stimulation but a reduction in sympathetic arousal.
	Auricular acupuncture has also been shown to suppress autonomic electrodermal activity associated with the startle reflex to arousing stimuli. Young and McCarthy conducted a controlled clinical trial on 38 healthy volunteers [59]. Forearm electrodermal recordings to different stimuli were obtained when a needle was inserted into the auricular sympathetic point. In another set of subjects, EDR levels were recorded when a needle was inserted into a placebo auricular point not associated with autonomic regulation. Evoked EDR activity was consistently higher when needles were placed in the placebo auricular point than when placed in the sympathetic point. Thus, there was a selective difference between the electrodermal effects of appropriate and inappropriate auricular acupuncture stimulation, suggesting that the auriculotherapy attenuated the autonomic startle reflex.
6.7

Mechanisms for Withdrawal from Opiate Drugs by Auricular Acupuncture

	The discovery by H. L. Wen [56] that auricular acupuncture facilitates withdrawal from narcotic drugs has led to a plethora of studies demonstrating the clinical use of this technique for substance abuse [13, 53]. Auricular electroacupuncture has been shown to raise levels of met-enkephalin in human narcotic addicts [10] and betaendorphin in mice withdrawn from morphine 1181.
	Kroening and Oleson 1271 examined 14 chronic pain patients switched from their original analgesic medication to an equivalent dose of oral methadone, typically 80 mg per day. An electrodermal point finder was used to determine areas of low skin resistance for the lung point and the Shen men point. Needles were bilaterally inserted into these two ear points and electrical stimulation was initiated between two pairs of needles. After 45 minutes of electroacupuncture, these hospitalized pain patients were given periodic injections of small doses of naloxone (0.04 mg every 15 minutes). The daily dose of methadone was cut in half each day, presuming no aversive withdrawal effects. All 14 patients were withdrawn from methadone within 2 to 7 days for a mean of 4.5 days. Only a few patients reported minimal side effects of mild nausea and agitation. The authors proposed that occupation of opiate receptor sites by narcotic drugs leads to the inhibition of the activity of natural endorphins, whereas auricular acupuncture facilitates withdrawal from these drugs by activating the release of previously suppressed endorphins. By giving small, incremental doses of naloxone administration after auricular acupuncture, it was theorized that opiate receptor sites can be allowed to return to their normal state.
	Other biochemical changes also accompany auricular acupuncture. Debrecini [ 14] examined changes in plasma adrenocorticotropic hormone (ACTH) and growth hormone levels after 20 Hz electrical stimulation through needles inserted into the adrenal point on the tragus of the ears of 20 healthy females. While growth hormone secretions increased after electroacupuncture, ACTH levels remained the same. Jaung-Geng et al. (23] evaluated lactic acid levels from pressure applied to ear vaccaria seeds positioned over the liver, lung, san jiao, endocrine, and thalamus (subcortex) points. In a within-subjects design, pressure applied to ear points produced significantly lower levels of lactic acid obtained after physical exercise on a treadmill test than when the seeds were placed over the same auricular points but not pressed. Actual stimulation of these auricular acupressure points seemed to reduce the toxic elevations of lactic acid buildup to a greater extent than did the control condition, perhaps due to improved peripheral blood circulation.
6.8

Conclusions

	One is constantly confronted with the need for further scientific studies to verify theoretical mechanisms in many areas of investigation, but this is especially true for neurophysiological studies of auricular acupuncture. Nonetheless, the studies thus far conducted indicate that there is already some support for each of the theoretical issues addressed at the beginning of this chapter. The two controlled studies on auricular diagnosis [39, 481 both support the proposition that specific areas of the auricle are related to specific areas of the body. The neurophysiological evidence for a connection between acupuncture stimulation and brain pathways related to a pain inhibitory system has been better established for body acupuncture than for ear acupuncture, but body points and ear points are both associated with endorphin and enkephalin release. Research in rats and rabbits has shown that stimulation of the vagus nerve via needling of the central concha of the ear selectively activates hypothalamic neurons associated with weight control [3, 491, whereas stimulation of the auricular lobe region representing the trigeminal nerve attenuates cortical evoked potentials to tooth shock [ 15, 24]. These animal studies suggest that stimulation of auricular points can lead to site-specific elevation of pain thresholds, but the relationship of somatotopic points on the auricle to specific regions of the human brain remains to be determined.
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Suggested Reading

	Chen B-Y (1997) Acupuncture normalizes dysfunction of hypothalamic-pituitary-ovarian axis. Acupunct Electrother Res 22:97-108
	Chen, H (1993) Recent studies on auriculoacupuncture and its mechanism. J Tradit Chin Med 13:129-143
	Hyvarinen J, Karlsson M (1977) Low skin resistance skin points that may coincide with acupuncture loci. Med Biol 55:88-94
	lonescu-Tirgoviste C, Pruan S, Bajenaru P (1991) The participation of the autonomic nervous system in the mechanism of action of acupuncture. Am J Acupunct 19:21-28
	Kashiba H, Ueda Y (1991) Acupuncture to the skin induces release of substance P and calcitonin gene-related peptide from peripheral terminals of primary sensory neurons in the rat. Am I Chin Med 19:189-197
	Kumar A, Tandon 0, Bhattacharya A, Gupta R, Dhar 1) (1995) Somatosensory evoked potential changes following electroacupuncture therapy in chronic pain patients. Anaesthesia 50:411-414
	Lin X, Liang J, Ren J, Mu F, Zhang M, Chen J (1997) Electrical stimulation of acupuncture points enhances gastric myoelectrical activity in humans. Am J Gastroenterol 92:1527-1530
	Ng L, I)outhitt T, Thoa N, Albert C (1975) Modification of morphine withdrawal in rats following transauricular electrostimulation: An experimental paradigm for auricular electroacupuncture. Biol Psychiatr 10:575-580
	Ng 1. (1996) Auricular acupuncture in animals: Effects of opiate withdrawal and involvement of endorphins. J. Compl Alt Med 2:61-64
	Reichmanis M, Marino A, Becker R (1976) I). C. skin conductive variation at acupuncture loci. Am J Chin Med 4:69-72
	Sjolund It, Terenius 1., Eriksson M (1977) Increased cerebrospinal fluid levels of endorphins after electroacupuncture. Acta Physiol Scand 100:382-384
	Takeshige C, Sato T, Mera T, Hisamitu T, Fang J (1992) Descending pain inhibitory system involved in acupuncture analgesia. Brain Res Bull 29:617-634
	Wang Y, Wang S, Zhang W (1991) Effects of naloxone on the changes of pain threshold and contents of monoamine neurotransmitters in rat brain induced by electroacupuncture. J Trad Chin Med 11:286-290
	Well H, Ho K, Ling N, Ma I., Choa G (1979) The influence of electroacupuncture on naloxone-induced morphine withdrawal. II. Elevation of immunoassayable beta-endorphin activity in the brain but not the blood. Am I Chin Med 7:237-240
	Wheeler A, Beitz I), Swift C (1976) Mapping of acupuncture points of the goat. Am ) Acupunct 4:57-65
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  CHAPTER 7

  Assessing Clinical Efficacy of Acupuncture: 
 What Has Been Learned from Systematic Reviews 
 of Acupuncture?

J. Ezzo • L. Lao • B. M. Berman

7.1

Introduction

	This chapter summarizes the evidence of the clinical efficacy of acupuncture. Treatment efficacy pertains to the differential effect observed from a treatment as compared to a placebo or another treatment using a rigorous methodological design. Efficacy is often assessed using a double blind controlled trial design [ 1 ]. While some chapters in this book focus primarily on animal studies, the question of clinical efficacy can only be addressed in human studies. Therefore, this chapter will focus on summarizing the evidence from human acupuncture trials. It is divided into two major sections. The first presents an overview of evidence-based medicine and explains why the systematic review is the most reliable and valid method for assessing efficacy. The second section summarizes the current evidence from systematic reviews on acupuncture for specific conditions and, when applicable, presents results of trials published subsequently to each systematic review.
7.2

The Role of Systematic Reviews in Evidence-Based Medicine

	Although there are many experimental designs in research, the gold standards for assessing efficacy are large, well-designed, randomized controlled trials (RCTs) and systematic reviews (Table 1) [2], because these designs are less likely to mislead than other study designs [3]. To date, trials of acupuncture are notably small [4-6], and few fulfill the description of a large RCT. Therefore, the most comprehensive assessment of acupuncture efficacy will be found in the existing systematic reviews on the topic.
	Until about the mid-1990s, the terms "systematic review" and "meta-analysis" were used interchangeably. That is why the review by ter Reit and colleagues [4] is termed a "meta-analysis." More recently, these terms have been clarified: A systematic review is the whole process of conducting a comprehensive evidence synthesis from search strategy, evaluation of trial quality, and analysis, whereas a meta-analysis is a specific statistical technique of pooling data. By today's definition the ter Reit chronic pain review is actually a systematic review without a meta-analysis. Examples of acupuncture systematic reviews which have used meta-analysis are the reviews of acupuncture for chronic pain by Patel and colleagues [30] and on acupuncture for smoking cessation by White and Rampes [31].
	 SPECIAL_IMAGE-page0149_0000.svg-REPLACE_ME 
	Evidence-based medicine is the "conscientious, explicit, and judicious use of the current best evidence in making decisions about the care of individual patients" [2]. This requires that clinicians combine their best clinical wisdom and experience with the best systematically researched clinical evidence available. It is not, as some have suggested [7], a reliance on abstract clinical evidence to the exclusion of clinicians' experiences and common sense. In essence, by applying their best clinical experience while keeping abreast of new research, clinicians have always striven to practice evidence-based medicine, which is why some have called it "old wine with a new label" [8].
	What is new about evidence-based medicine is the systematic review method, which is an explicit methodology designed to summarize and synthesize evidence [3[. In the past, traditional literature reviews, commonly called narrative reviews, have been used to summarize evidence. One major difference between narrative reviews and systematic reviews is that systematic review methodology requires all trials which meet specified criteria to be included in the review, regardless of the trial results. By contrast, narrative reviews may exclude trials with findings that did not match the writer's point of view or had simply been inadvertently haphazard and noncomprehensive and therefore prone to bias [9[. Experience has demonstrated that a treatment which appears promising according to a narrative review can appear less promising when the systematic review methodology is applied [ 101. Because systematic reviews follow an explicit methodology designed to minimize bias, they are becoming increasingly preferred over narrative reviews. For example, policy makers are growing increasingly partial to them as a way of summarizing evidence [ 11 [. And, in the midst of the information explosion, clinicians rank reviews as their most preferred source of new information [ 121 while ranking individual RCTs close to the bottom of the list. Consumers, too, can use reviews to guide health decisions 1131.
	Finally, because systematic reviews comprehensively summarize research already completed, they are valuable tools for guiding the design of proposed clinical research. Systematic reviews can prevent the inadvertent duplication of work already done, underscore where knowledge gaps exist, and generate hypotheses for future research. For these reasons, trialists advocate conducting a systematic review and meta-analysis in the planning stages of a trial [14, 151, and funding agencies are increasingly inquiring on grant applications whether a systematic review has been conducted on the topic for which funding is sought [ 16].
7.2.1

Validity of the Study Design: How Systematic Reviews Limit Bias

	It is important to understand the systematic review process in order to appreciate how this type of data analysis can limit bias. McQuay and Moore [2] describe the following as key steps of any systematic review: finding, appraising, and combining the evidence. Bias, a systematic error which can make a treatment appear less or more effective than it really is, can occur in any stage of this process. Although the examples presented here pertain to acupuncture, the potential biases discussed below apply to all systematic reviews for any treatment of any condition.
7.2.1.1

Finding the Evidence

	One of the most striking ways that systematic reviews differ from narrative summaries is the comprehensiveness of the search for relevant trials. A trials search should be both comprehensive and replicable. MEDLINE is the most obvious place to begin searching for relevant acupuncture trials, but a search should not stop there. MEDLINE sensitivity, which is the proportion of relevant RCTs found by MEDLINE divided by the total of known trials on the topic, is estimated to be only about 58 % for acupuncture [ 17]. Obviously, this suggests that a universe of acupuncture trials exist that are not listed in MEDLINE. Additional sources can include other electronic databases [ 18], articles in journals not indexed by any database, conference abstracts that never become fully published articles, and trials which are completed but remain in researchers' file drawer or diskette and never reach print at all [19].
	Publication bias is "the tendency of investigators, reviewers, and editors to submit or accept manuscripts for publication differentially, based on the direction or strength of the findings" [20[. Therefore, articles which are the most easily accessible because they are published may not be representative of the results of all the trials done. To the extent that publication bias exists, systematic reviews that omit unpublished studies risk overestimating treatment effects. Bias has been demonstrated both in what investigators submit to journals [21] and in what editors accept [221.
	The recent findings by Egger and colleagues [23] raise the question of whether trials published in English are representative of the available trials. They observed that authors publishing in both German and English tend to report nonsignificant findings in German and significant findings in English. This suggests that one must search not only beyond the published literature, but also beyond the English language.
7.2.1.2

Appraising the Evidence

	It may seem obvious that evidence is only as good as the trials upon which it is based, but the concept of assessing the methodological quality of the trials included in a systematic review is a relatively recent practice. A validated, user friendly scale (Jadad scale) for assessing methodological quality did not exist until 1996 (Table 2) [24]. Therefore, many reviews exist which form conclusions about the efficacy of a treat ment without taking into consideration the quality of the individual trials. The Jadad scale asks two questions pertaining to double blinding (defined as blinding both the patients and the outcomes assessor). Because it is not possible to blind the patients in most acupuncture trials, some reviewers have used a slightly different scale [6] which asks two separate questions: (1) Were the patients blinded? and (2) Was the outcomes assessor blinded? However, even if double blinding did not occur, it is still possible for a trial to earn a high quality score on the Jadad scale if the trial quality was satisfactory in other areas.
	When trial quality is taken into account, results show that all RCTs are not created equal and, in general, low quality RCTs can bias trial results by exaggerating the positive effects of a treatment 125, 261. Relative to acupuncture in particular, low quality RCTs have been associated with results favoring acupuncture for chronic pain 14, 271, asthma 151, and tobacco addiction [281.
	Previously, many also assumed that RCTs not published in English were likely to be inferior methodologically compared to those in English, and therefore non-English language studies were often omitted from systematic reviews. Recently, Moher and colleagues [29] have demonstrated that the quality of studies in French, German, Spanish, and Italian is comparable with those published in English and, therefore, excluding these trials from a systematic review cannot be justified.
7.2.1.3

Combining the Evidence

	Meta-analysis, the statistical pooling of results, is a preferred way to combine data from several trials when the data permit [2]. When the data are not conducive to pooling, an alternative method known as best evidence synthesis [32], which gives more weight to the high quality trials and less weight to low quality trials, is preferred over a simple one-trial, one-vote method. The latter method is discouraged because low quality trials should not be given the same weight as high quality trials. The reviews on acupuncture for low back pain by Tulder and colleagues [33] and for chronic pain by Berman and colleagues [27], demonstrate this approach.
	As has already been noted, bias can occur if high quality studies are combined with low quality studies. One way to assess whether low quality studies may be biasing results is to perform a sensitivity analysis. This method combines the results of both high and low quality trials and compares these results to those of the high quality trials alone. If the combined low and high results appear more optimistic than the high quality results alone, then bias may be at work.
	Bias can also occur if the reviewers inadvertently count the same trial twice (duplicate bias). Duplicate bias occurs when two articles appear sufficiently different so that the reviewers fail to realize that they actually represent the same trial. If the duplicate trial has a positive result, it biases results towards the positive side, whereas, if the trial has a negative or nonsignificant result, it biases results the other way. Duplicate bias is no small problem in systematic reviews and can exaggerate a treatment effect by as much as 20% [34].
	 SPECIAL_IMAGE-page0153_0000.svg-REPLACE_ME 
7.2.2

Validity of the Acupuncture Procedure: Assessing the Quality of the Acupuncture Treatment

	So far, most of the discussion about trial validity has concerned how the methodological quality of trial design can bias trial outcome. However, inadequate acupuncture treatment can also jeopardize trial validity and bias outcome. Basing conclusions about acupuncture efficacy on suboptimal or inadequate acupuncture procedures is analogous to pharmaceutical trials formulating conclusions about the efficacy of drugs based on inadequate dose. While some conditions such as nausea and vomiting have a straightforward, commonly accepted acupuncture procedure (i.e., the stimulation of P6), other conditions such as chronic pain have tremendously different treatment approaches. Therefore, the question of acupuncture treatment adequacy is more urgent for some conditions than for others. Although it is an issue to be addressed and defined in primary studies (e.g., cohort studies or RCTs), systematic reviews must have a method for assessing whether treatments meet basic criteria. Three methods have been used to assess the adequacy of acupuncture procedures retrospectively.
	One way that reviewers have retrospectively assessed acupuncture treatment adequacy was first proposed by Linde et at. [6]. An acupuncturist was presented with the inclusion criteria and acupuncture methods in the papers, blinded to trial results, and asked to rate whether the acupuncture treatment was adequate to treat the condition under investigation based on five aspects: (1) points selected, (2) total number of treatments, (3) number of times per week the patient was treated, (4) duration of each session, and (5) whether or not "de qi" was elicited.
	A second way of assessing acupuncture treatment quality retrospectively is to specify a minimally acceptable treatment. This approach, used by Molsberger and Bowing [35], defined a minimally adequate acupuncture treatment as consisting of at least ten total treatments of at least 15 minutes each and a description of the points used. Only 16 of 88 studies on musculoskeletal and/or neurological conditions met the minimal criteria and, of those, only two were controlled trials. What was learned from this method is that most studies do not meet the minimal criteria of an acceptable acupuncture procedure.
	A third, less efficacious approach to quantifying acupuncture procedure is to identify those aspects of the acupuncture procedure that are associated with positive outcomes. Although this cannot answer the question of whether the treatment is adequate, it can provide important information for guiding future clinical trials. Patel and colleagues [30] used this approach with their pooled data. They noted that individualized treatments significantly favored acupuncture, whereas formulaic approaches, in which all the patients received the same treatment, fared less positively. They proposed that individualized acupuncture treatments might produce better outcomes than cookbook approaches but that these findings could be confounded by the methodological quality of the trials.
	This third approach was also used in a recent acupuncture and chronic pain review [27]. The specific aspects of the acupuncture treatment which were hypothesized as associated with positive outcomes were based on findings reported in a doctoral thesis [36]. The thesis analyzed the acupuncture procedures in textbooks from China, Japan, and Korea seeking recommendations which could be generalized for treating certain pain conditions. No generalized recommendation could be made on the specific acupuncture points, because they varied so much from textbook to textbook. On the other hand, generalizations could be made pertaining to the recommended number of needles used and the number of total treatments administered: 6 points per treatment were probably adequate but 10 were better, and six total treatments were probably adequate but ten were better. When these hypotheses were tested in the chronic pain review [27], no association was observed between the number of points used and positive outcome, but a statistically significant association (p< 0.05) was found between the total number of treatments given and the outcome, even when controlling for methodological quality of the trials. Interestingly, virtually no trial administering fewer than six acupuncture treatments achieved a positive outcome.
	Although these significant findings merely show an association and not a causal relationship between six or more treatments and positive outcome, like Patel's observation about individualized treatments, they may be able to guide future studies. Given the paucity of information as to what constitutes an adequate acupuncture treatment, it is advisable to compare the effectiveness of various acupuncture protocols in a small pilot study to ascertain the preferred procedure before conducting a larger RCT. One common problem in assessing an acupuncture procedure retrospectively is that very few trials present sufficient information about the acupuncture procedure to assess its adequacy. For example, data on the various aspects of the acupuncture treatment were extracted for one chronic pain review ]27] but found to be insufficient for assessment. The problem of missing information was also encountered by ter Reit and colleagues [4] when they attempted to use a proxy measure for treatment adequacy by assessing whether the papers reported on the extent of training and experience of the acupuncturist. What has been learned from this method is that reporting on the details of the acupuncture procedure needs to be improved in trials.
7.2.3

Summary

	In conclusion, summarizing evidence can be likened to Aesop's story of the blind men and the elephant:
	Each of five blind men is asked to touch an elephant and describe what the animal looks like. One blind man feels the tail and claims the animal is long and thin like a rope. Another, feeling the elephant's leg, insists that the animal is round, thick, and solid like a tree trunk. And so on.
	As children hearing this story, we were amused at the obvious foolishness of each man forming an opinion of the elephant based on one small study. Now, as researchers and clinicians, we are challenged to transcend the mistaken assumption that one small study represents the whole reality. Small RCTs, which are typical of current acu puncture trials, seldom answer efficacy questions definitively. A trial may lack sufficient power to detect a difference that exists in reality (known as a type II or false negative error), it may be biased, or the results may be applicable only to a certain group of people or patients but not to all. There are many advantages to using the systematic reviews method (Table 3). In short, this offers the most comprehensive way to describe "the elephant."
7.3

A Summary of the Results of Systematic Reviews of Acupuncture

	This section summarizes the results of systematic acupuncture reviews. The first part of this section will summarize the systematic reviews which have been done for painful conditions. The remaining part will summarize the results of systematic reviews for other conditions, such as acupuncture for nausea and vomiting or for asthma (Table 4).
7.3.1

Acupuncture for Painful Conditions

7.3.1.1

Is Acupuncture Effective for Chronic Pain?

	Patel and colleagues [30] published the first systematic review on chronic pain, observing that few of the 14 acupuncture trials included had statistically significant results. However, the pooled results favored acupuncture. Furthermore, pooled subgroup analyses by site of pain significantly favored acupuncture for low back pain and head/neck pain. However, statistical pooling produced another interesting finding: when trials with some degree of blinding (of patients and/or outcomes assessors) were compared to trials with no blinding, the unblinded trials significantly favored acupuncture, whereas the blinded trials did not. One interpretation for this is that lack of blinding may have biased the results to favor acupuncture. Other methodological deficiencies were also noted, and the more methodologically rigorous trials tended to yield less favorable results. Because of this, the authors stated that, although the pooled results favoring acupuncture were statistically significant, the various sources of bias prevented this finding from being a definitive conclusion.
	Ter Reit and colleagues [4] published a more extensive systematic review on chronic pain the following year, including an extensive search strategy and a way of scoring trial methodology. Their findings were inconclusive, noting that no studies emerged as high quality, making it impossible to draw definitive conclusions.
	 SPECIAL_IMAGE-page0158_0000.svg-REPLACE_ME 
	 SPECIAL_IMAGE-page0159_0000.svg-REPLACE_ME SPECIAL_IMAGE-page0160_0000.svg-REPLACE_ME 
	In the decade since the ter Reit review was published, a validated quality assessment scale has been developed (Table 2) [24], a notable number of high quality randomized trials of acupuncture for chronic pain have been published, and, due to the formation of the Cochrane Collaboration [52], systematic review methodology has become more explicit. Therefore, the question of acupuncture for chronic pain was recently revisited in another systematic review which used the best evidence synthesis method (Table5) [27]. There, a slightly different efficacy question is asked depending on the comparison group used in an acupuncture trial. In the best evidence synthesis review [27], the comparison groups were therefore categorized according to the similarity of the question being answered. The results by type of comparison group were: limited evidence that acupuncture is more effective than no treatment (waiting list) and inconclusive evidence that acupuncture is more effective than inert placebo (sham TENS or sugar pills), sham acupuncture, or standard medical care.
7.3.1.2

Is Acupuncture Effective in the Treatment of Low Back Pain?

	Although Patel and colleagues [301 found acupuncture to be effective in low back pain in meta-analysis, they warned that the results should be interpreted with caution because of design flaws. Tulder and colleagues 1331 recently revisited the question of acupuncture for chronic low back pain using the best evidence synthesis method (Table 5). Nine of the 11 trials included were of low quality and had small sample sizes. The contradictory results and few high quality RCTs were the reasons given that the authors classified the evidence as level 4 (Table 5), concluding there is no evidence that acupuncture is an effective treatment for chronic low back pain.
	Since the systematic review was published, Molsberger and colleagues [38] have completed a large, methodologically rigorous trial assessing two questions: (1) Can acupuncture contribute as an adjunctive therapy to the conservative management of LBP? and (2) Is real acupuncture superior to sham acupuncture? In a three-arm parallel group design, 186 low back pain patients with pain for more than 6 weeks and a pain intensity score greater than 50 on the visual analogue scale (VAS) were randomly assigned to one of three groups. Patients in all groups received a baseline treatment consisting of conservative orthopedic therapy everyday.
	 SPECIAL_IMAGE-page0161_0000.svg-REPLACE_ME 
	Real acupuncture, consisting of 12 acupuncture treatments at 30 minutes each, was added to this baseline treatment in group 1. Sham acupuncture consisting of 12 sham treatments at 30 minutes each was added to the baseline treatment in group 2. Group 3 received baseline treatment only. Patients in both acupuncture groups were blinded and the outcomes assessor for all three groups was also blinded. The primary outcome was a pain reduction of 50 % or more on the VAS at 3 months after the end of treatment. Achievement of the primary outcome by group, based on intention-totreat analysis, was: real acupuncture 76.6 %, sham acupuncture 29.3 %, and conservative orthopedic therapy 13.9 %. Additionally, for low back pain patients with pain over more than 5 years, the relative probability of experiencing 50 % or greater pain reduction was 10 times higher in real acupuncture than sham. The investigators concluded that real acupuncture is an important supplement in the management of chronic low back pain.
7.3.1.3

Is Acupuncture Effective in the Treatment of Osteoarthritis?

	Of the 13 trials included in a recent systematic review [39], results were equivocal, with seven demonstrating positive results and six demonstrating nonsignificant results. Design flaws noted in the trials with positive findings included failure to control for placebo effects and lack of randomization. When RCTs were considered separately, results were still equivocal, with five trials having positive results and five having nonsignificant results. Ernst observed that four of the five trials comparing real acupuncture to sham acupuncture yielded nonsignificant findings.
	Two large trials, both with positive findings, were not included in this systematic review 140, 411. In a comparison of real vs. sham acupuncture (n = 97), Molsberger and colleagues 1401 found that real acupuncture significantly outperformed sham acupuncture for pain relief at 3 months following the end of the acupuncture treatment (p< 0.05). However, functional improvement did not differ significantly between groups.
	A second trial [411 comparing acupuncture as an adjunct to standard medical care vs. standard medical care alone, showed significantly more improvement in the acupuncture group (p< 0.05) in both pain and functional indices. These significant differences continued to be observed at both 4 and 8 weeks follow-up.
	The results of these two trials, which were notably larger than the trials included in the systematic review, raise the question of whether the nonsignificant results of the earlier trials were a result of small sample size (type II error) rather than the equi- vocacy of the two treatments.
7.3.1.4

Is Acupuncture Effective in the Treatment of Fibromyalgia?

	A recent systematic review of acupuncture for fibromyalgia syndrome (FMS) included both RCTs and cohort studies [42]. It was decided a priori that high quality RCTs would be used for hypothesis (efficacy) testing, whereas low quality RCTs and cohort studies would be used for hypothesis generation. Quality assessment revealed only one high quality RCT. Scoring a perfect quality score, the one high quality RCT [43] demonstrated that real acupuncture is more effective than sham acupuncture in relieving pain, increasing pain thresholds, and improving global ratings. However, because long-term follow-up was not performed, the duration of benefit following completion of the acupuncture series could not be ascertained.
	Based on the outcomes in the studies used for hypothesis generation, three important questions were raised:
	1. Can booster doses sustain benefit in responders? The use of periodic booster doses of acupuncture was anecdotally described in two cohort studies as an effective way to sustain benefit in responders, once regular sessions ceased, but remains to he tested in an RCT.
	2. What is the optimal acupuncture treatment for FMS? The high quality RCT used a combination of low and high electrical frequencies, which is consistent with acupuncture analgesia literature suggesting that optimal pain relief can be achieved by combining low (2-4 Hz) and high (50-100 Hz) frequencies [43]. However, comparing the combined frequencies approach to other approaches remains to be tested in the same fibromyalgia population.
	3. Does acupuncture work synergistically with antidepressant medication? One study noted that the combined use of acupuncture and antidepressants appeared to be more globally effective across the many dimensions of pain, depression, and sleep than either acupuncture or antidepressants alone, suggesting synergistic benefits of acupuncture plus medication 144]. However, due to methodological shortcomings of the study, the synergism remains to be tested under rigorous conditions.
7.3.1.5

Is Acupuncture Effective in the Treatment of Acute Dental Pain?

	Ernst and Pittler concluded in a systematic review that acupuncture is effective in alleviating pain during or after dental operations [45]. This is consistent with the NIH consensus panel opinion that "there is evidence of efficacy for postoperative dental pain ] 1 ]" Mechanisms of action for the analgesic effects may be endorphin release, afferent pathway blockade, and/or efferent pathway inhibition. They noted that the methodological details and quality varied among studies, which limited the generalizations that could be made. Among the most common methodological shortcomings cited were non randomization, lack of control for placebo effects, and small sample sizes. The wide variation in types of acupuncture used precluded generalizations about which procedure was superior.
	Since this systematic review was published, an additional RCT (n = 39) comparing real vs. placebo acupuncture has been published which further substantiates the efficacy of acupuncture for dental pain ]46]. Outcomes included were patients' selfreports of duration until moderate pain, time until use of medication, total pain relief, pain half gone, and total pain medication consumption over 7 days. Results demonstrated that the mean pain-free postoperative time was significantly longer in the acupuncture group than in the placebo acupuncture group (p = 0.01), as was duration of time until moderate pain (p = 0.008). The time until use of medication was significantly longer in the acupuncture group (p = 0.01).
	In addition to giving more evidence that acupuncture is effective in the treatment of dental pain, this recent RCT makes three other important observations:
	1. Acupuncture was significantly superior to placebo acupuncture in preventing pain before it began but was not more effective than placebo acupuncture after the pain had reached moderate intensity. This observation may suggest that acupuncture is most effective when administered preemptively rather than once the pain begins.
	2. When compared to real acupuncture, placebo acupuncture was associated with more adverse effects directly related to the tooth excision procedure. This may suggest that real acupuncture is protective against some of the adverse effects of surgery.
	3. The dental pain technique used in this study is a commonly accepted acute pain model used to assess analgesic drugs. The favorable findings of acupuncture using this model suggest that acupuncture may be valuable as an analgesic for other types of acute pain besides dental pain.
7.3.1.6

Is Acupuncture Effective in the Treatment of Headache?

	Melchart and colleagues [47] conducted a systematic review assessing the efficacy of acupuncture in the treatment of tension headache and migraine. To score the results for each included trial, at least two reviewers voted on each trial using the following five categories as the classifications: (1) control significantly better than acupuncture, (2) trend towards control group, (3) no difference, (4) trend towards acupuncture, and (5) acupuncture significantly better than control.
	The overall results using this method in trials comparing true vs. sham acupuncture in migraine and tension headache patients showed a trend in favor of true acupuncture. A more definitive statement could not be made, because most trials were small with either methodological or reporting limitations. Furthermore, due to variations in patients, trial quality, and types of acupuncture procedures used, a clear recommendation as to what constitutes the best acupuncture treatment could not be made. The trials comparing acupuncture to other headache treatments yielded insufficient evidence to assess whether acupuncture is as effective as standard medical care.
	The reviewers concluded that acupuncture might have a role in the treatment of recurrent headaches, stating that although acupuncture is not completely risk-free, it is generally safe in the hands of adequately trained practitioners and, therefore, there is no reason to discourage headache sufferers interested in trying acupuncture. The reviewers also concluded that the data are not conclusive enough to justify recommending acupuncture nor can the data ascertain what kind of acupuncture is most effective for headache.
7.3.2

Acupuncture for Other Conditions

7.3.2.1

Is Acupuncture Effective in the Treatment of Asthma?

	One proposed mechanism of action by which acupuncture intervenes in asthma is through the release of adrenocorticotropic hormone by the pituitary gland, which in turn results in the release of adrenal corticosteroids, a natural anti-inflammatory agent. In 1991, Kleijnen and colleagues [5] first explored the clinical evidence by assessing both randomized and nonrandomized trials. The results were inconclusive and, in 1996, Linde and colleagues [6] revisited the question, looking at only RCTs. The overall trends were similar in both reviews: the benefits of acupuncture for asthmatic attacks were inconsistent among studies. Benefits measured in long-term follow-up were characterized more by subjective reports of improvement than by objective improvements in pulmonary function.
	Although the findings were equivocal, their interpretation varied. Linde and colleagues concluded that "up to now, there is insufficient data from randomized clinical trials to assess reliably the efficacy and effectiveness of acupuncture in the treatment of asthma 161" In a narrative review, ]obst offered a more generous interpretation, saying that there is "no reason to withhold acupuncture as a safe and potentially effective treatment in patients with bronchial asthma and chronic obstructive lung disease" 148].
	The most important issue raised by the review by Linde et al. is that only one trial compared acupuncture to standard care or as an adjunct to standard care. The authors emphasized that trials comparing sham vs. real acupuncture are not clinically useful and do not assess acupuncture as it is actually used in practice. Because standard care is already quite effective for asthma, the choice to use acupuncture should not be made in place of standard care, but rather as an adjunct to it. In fact, avoidable deaths from asthma have been reported when patients have refused conventional care in preference for acupuncture [49]. The best recommendation based on the available evidence comes from the NIH consensus panel: "acupuncture treatment for asthma should be part of a comprehensive management program" [ 1 ]. Whether acupuncture has some adjunctive benefit as part of a comprehensive asthma treatment program remains to be seen. What is certain is that trials comparing real and sham acupuncture or a placebo offer little of substantial clinical relevance. Furthermore, it is also unethical to withhold treatment when effective standard care exists.
7.3.2.2

Is Acupuncture Effective in the Treatment of Nausea and Vomiting?

	Perhaps the most compelling and consistent evidence for the efficacy of acupuncture is in the treatment of nausea and vomiting [50]. Of the 29 trials in which acupuncture was used while the patient was fully awake (not under anesthesia), 27 favored acupuncture. When only trials of the highest methodological quality were examined, 11 out of these 12 trials, representing nearly 2000 patients, showed positive results. The positive results are strikingly consistent, although the high quality trials represent different investigators, patients, and an assortment of ways in which P6 was stimulated. These findings are summarized by the NIH consensus panel in its affirmative statement that "there is clear evidence that needle acupuncture is efficacious for adult postoperative and chemotherapy nausea and vomiting and probably for the nausea of pregnancy" [ 11.
	Interestingly, the four trials in which P6 was stimulated while the patients were under anesthesia all demonstrated acupuncture to be ineffective in preventing nausea and vomiting. The reason for this is not clear. However, Vickers offers three possibilities: (1) P6 stimulation may behave like conventional antiemetic drugs and must be administered preemptively, before the emetic stimulus occurs, (2) the mechanism of action may require an intact nervous system, or (3) acupuncture may work by psychological mechanisms. This last possibility is unlikely, however, because stimulation of a fake point consistently has a lower antiemetic effect than P6, even though the fake points are credible to patients. That inappropriately high levels of P6 stimulation can increase nausea and vomiting also argues against the effects of P6 as a purely psychological phenomenon.
7.3.2.3

Is Acupuncture Effective in Smoking Cessation?

	The 16 studies included in a systematic review [31] were methodologically inadequate in that they seldom reported details of randomization or used biochemical indicators to validate self-reports of smoking cessation. Variations in trial quality made it difficult to ascertain whether one type of acupuncture (e.g., auricular vs. body acupuncture) was superior.
	The pooled results demonstrated that real acupuncture provided no statistically significant benefit compared to sham acupuncture or other antismoking treatments at any time point (less than 6 weeks, at 6 or 12 months). This is consistent with the NIH consensus opinion that "there is evidence that acupuncture does not demonstrate efficacy for cessation of smoking" [I]. In the short run, acupuncture appeared to be better than doing nothing (no intervention). However, this benefit attenuated over time and had disappeared by 6-month follow-up. The negative conclusion of this review suggests that research should focus on whether acupuncture can ameliorate the adverse symptoms of acute withdrawal rather than provide long lasting cessation of tobacco use. One question not addressed in this review is whether long lasting cessation may have been achieved, had acupuncture treatments been continued.
7.3.2.4

What Can Be Learned in Trials Comparing Acupuncture to Standard Medical Care?

	Generally, systematic reviews address a specific clinical question. However, systematic review methodology can also be used to answer methodological questions. For example, it is of great interest to the scientific community to know how acupuncture compares to standard medical care. Hammerschlag and Morris recently examined how well this type of important trial has been performed and presented [51]. They included only trials for which standard care was either cited or computer-search identified as previously having outperformed placebo in an RCT. Trials were selected independently of outcome. Only three of the 23 studies were rated as adequate on at least 60% of the evaluation criteria. Two of the most important elements of a trial showed very different scores: randomization was reported in 20 (87 %) of the trials, whereas blinding of the outcomes assessor was reported in only four (17%).
	Their summary also highlights what can be learned from the highest quality studies: "By reviewing those studies that were scored adequate for each criterion, informative examples can be gleaned: acupuncture had a more rapid analgesic onset than Avafortan for relieving renal colic; when used as adjunctive treatment to physical therapy, acupuncture enabled a significantly greater percent of low back pain patients to return to their original or equivalent jobs relative to those treated with physical therapy alone; and while acupuncture was as effective as the beta blocker metoprolol for reducing the frequency and duration of migraine attacks, it had fewer side effects but was patient-rated as less effective than metoprolol in global effect on headaches [51].
7.4

Looking to the Future: The Role of the Cochrane Collaboration in Conducting and Maintaining Systematic Reviews

	The Cochrane Collaboration was formed in 1993 with the explicit and sole purpose of conducting, maintaining, and disseminating systematic reviews relevant to all aspects of health care )52). For systematic reviews to be optimally valuable to users, reviews must be widely disseminated and regularly updated to accommodate new information as it becomes available. To meet the growing need for systematic literature reviews as a way of synthesizing evidence and contributing to evidence-based medicine, Cochrane reviews have an explicit and transparent methodology, are peer reviewed, use an electronic format conducive to regular updates, are consumer reviewed to ensure readability, and have been available on MEI)LINE in abstract form as of 1999. Therefore, the Cochrane Collaboration offers health care a forum of international and interdisciplinary cooperation and an important vehicle for timely and accessible dissemination of evidence.
	The complementary medicine field within the Cochrane Collaboration [53, 541 specializes in producing systematic reviews related to complementary medicine, including acupuncture. In the future, we believe that the Cochrane Collaboration will be one of the most important vehicles serving clinicians, consumers, researchers, and policy makers who want timely and comprehensive summaries on the clinical effectiveness of acupuncture'.  
	Acknowledgement. We would like to express our appreciation to Victoria Hadhazy, MA, for her kind assistance in preparing this manuscript.
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	51. Hammerschlag R, Morris MM (1997) Clinical trials comparing acupuncture with biomedical standard care: A criteria-based evaluation of research design and reporting. Complement Ther Med 5:133-140
	52. Bero L, Rennie 1) (1995) The Cochrane Collaboration: preparing, maintaining, and disseminating systematic reviews of the effects of health care. JAMA 274(24):1935- 1938
	53. (1998) The complementary medicine field module. The Cochrane Library Jdatabase on disk and CI)-ROME. Vol. 4 Update Software, Oxford
	54. Ezzo J, Berman It, Vickers A, Linde K (1998) Complementary medicine and the Cochrane Collaboration. JAMA 280:1628-1630
  CHAPTER 8

  An Overview of Acupuncture in the Treatment 
 of Stroke, Addiction, and Other Health Problems

S. Birch

8.1

Introduction

	Acupuncture has been used and tested in a wide range of health problems [ 161. Often there are only one or two studies in a particular area and systematic reviews have thus not yet been possible. This chapter will focus on a number of areas with at least two controlled clinical trials or at least one controlled and one noncontrolled clinical trial. This is not a systematic review; rather it is an overview of the quality of the clinical trials in these areas. It is also not intended to be an exhaustive review but more as an introduction and overview of important areas where as yet limited research has been done. The chapter is thus an overview of potentially promising areas where acupuncture is used and further clinical and scientific work should be focused.
	The central theme of this chapter, the quality of research, was chosen in part because there are not enough studies in each area to draw clear conclusions about efficacy and in part because reviewers have found a wide range of methodological problems in clinical trials of acupuncture [2, 4, 14, 15, 19, 27, 31, 34, 35, 37, 38, 49, 50, 52, 55, 58, 60, 76, 81, 83-85]. Key problems we found are inadequate sample size, inadequate treatment, inappropriate control treatment, inadequate follow-up, inadequate control of nonspecific effects, inadequate reporting of side effects, and a few studies' failure to replicate results. These problems make it very difficult to draw clear conclusions about efficacy in most areas where acupuncture has been tested, including those covered in this chapter. Some studies clearly show good or very promising results 11, 22, 43, 70], but much better quality research is needed [4]. A recent U. S. National Institutes of Health consensus development conference on acupuncture listed stroke rehabilitation and addiction among a number of clinical conditions as "disorders for which the research evidence is less convincing but for which there are some positive clinical trials" [4]. There has been enough good research for discussion but not yet enough to draw clear conclusions.
8.2

Preliminary Analysis

	A wide range of control groups has been used in these studies. Acupuncture has been compared to various forms of control acupuncture, to standard care, placebo medication, placebo transcutaneous electrical nerve stimulation (TENS), no treatment, and historical controls, i.e., in retrospective comparisons with results from other studies.
	This diversity of models makes the task of designing and performing systematic reviews or meta-analyses more difficult. For example, the fact that acupuncture does not outperform a standard therapy is not necessarily a negative result. As long as it has the same or less cost and the same or fewer side effects, it remains a viable treatment option, and thus results could be interpreted positively. But if acupuncture does not significantly outperform in comparisons with control acupuncture, this tends to indicate that the acupuncture is not effective. It becomes difficult to make a straight comparison of these two models. Also, in studies where the efficacy of acupuncture was examined in something like ease and pain of childbirth, it is not necessary to make long-term assessments to find clinically significant results. But in other studies it is essential that long-term results be examined to achieve clinical significance. Thus, not all studies are comparable on the criterion of length of follow-up.
	In general, there has been a major problem with the inadequate treatment often administered in acupuncture studies 115, 731. If a control acupuncture model is used, it is important that the control treatment is appropriate. A study using a needling treatment as valid as the test acupuncture treatment is not appropriate for controls [15]. In studies that use control acupuncture or placebo control design, some researchers have suggested that it is not enough simply to state that the study was placebo-controlled but that the nonspecific effects must also be assessed using, for example, the credibility scale 114, 82, 84]. Studies using placebo or control acupuncture designs without these assessments can be difficult to interpret. In many, the treatments are also inadequately described, so that the studies become nonreproducible and are therefore less useful 1151. Further, to avoid bias, studies comparing acupuncture to standard care generally need larger sample sizes, as it is more likely that the treatment effects will appear similar with smaller numbers. Some analyses have found that the quality of acupuncture research appears to be improving over time [381; thus it is useful to consider whether later studies are better than earlier ones. These general issues are all important in an examination of the areas covered in this review.
	This review will not prejudge which methodology to use. There has been a wide range of research models applied in acupuncture studies 14, 37, 50], each with advantages and disadvantages. Each answers different questions and has specific study design needs. Some of the needs to be met are dependent upon the research design; some are independent. For example, adequate acupuncture treatment needs to be applied, regardless of the study design. Researchers have shown that this is a major problem in acupuncture studies, with suboptimal or completely inadequate treatments often being administered ] 14, 15, 73]. There is also a need for the treatment to be properly described so as to allow readers to assess what was done. This, too, has been a frequent problem ] 15].
	Different reviewers have used varied criteria to rate or judge the quality of clinical trials [27, 34, 38, 50, 52, 60, 65, 68, 76]. Since the present review is also intended as an assessment of the quality of acupuncture trials, the author has chosen the following design criteria.
8.3

Primary Evaluative Criteria

	The 33 studies were examined according to the following criteria:
	1. Was the study randomized?
	2. Was there an adequate description of the acupuncture treatment (possible answers: yes/no)?
	3. Was the acupuncture treatment adequate (yes/possibly/no/unclear)?
	4. Was the training of the acupuncturist mentioned (yes/no/not applicable)?
	5. Was the control treatment (CT) adequately described (yes/no/not applicable)?
	6. Was the CT appropriate (yes/no/unclear/not applicable)?
	7. Was a sample size calculation presented (yes/no/not applicable)?
	8. Were the evaluators blinded (yes/no/not applicable)?
	9. Was there follow-up after 3 or more months (yes/no/not applicable)?
	10. Were side effects monitored and presented (yes/no)?
	Items 2-6 relate to important design issues of controlled acupuncture trials. Items 1 and 7-10 are relevant for virtually any controlled clinical trial.
8.4

General Findings

	In Tables 1-8, one can see the following: the 33 studies were published in the period from 1985 to 1999, inclusively. The majority used a prospective active (noninert) control treatment (26/33). Overall, 29 studies found results favoring acupuncture. Dividing the studies in half, 16 were published in the period 1985-1993 and 17 in 1994-1999. Taking this arbitrary division, one can see a general trend toward less use of the control acupuncture model and more use of the standard care model. Sample sizes in the 1994-1999 trials increased considerably compared to the earlier, 1985-1993 trials: the range increased from 16-100 to 24-878, the median increased from 35 to 49, and the mean increased from 41.8 to 129.2.
	Tables 9-11 present the results of the analysis for each of the 33 papers. Table 12 summarizes these results in relation to the ten criteria. With regard to issues particularly relevant to acupuncture trials: the majority of the studies (31) had an adequate description of the treatment. The treatment was clearly adequate in only 17. The qualifications of the acupuncturist were mentioned in only eight. The majority of the studies that needed to describe the control treatment gave an adequate description (20/27). The majority appeared to use an appropriate control treatment (17/28). With regard to general study design, one can see that the majority of the studies were randomized (25/30) and used blinded evaluators (19/28), only 13 of 25 included followup of 3 months or more, and only 16 of 33 mentioned side effects.
	Table 12 also presents a summary comparison of the results of the 16 studies published in 1985-1993 and the 17 studies published in 1994-1999. One can see that studies in both time periods are comparable on all the criteria. Surprisingly, many studies in the latter period did not follow the methodology recommendations made in a number of important review papers published in the former period [55, 60, 65, 68, 76, 81, 83, 85]. For example, only 5/17 studies mentioned the qualifications of the acu puncturist, only 8/17 studies mentioned side effects, and only 9/15 used blinded evaluators. Additionally, definitely two and possibly seven more of the 17 studies still applied inadequate acupuncture treatments. However, later studies tended to use larger sample sizes and were more likely to use longer-term follow-up.
8.5

Possible Roles of Acupuncture

	It is useful to examine briefly each of the major areas included in this review. Since stroke rehabilitation and addiction treatment were covered in the National Institutes of Health Consensus Development Conference and mentioned in their final report [4], it is useful to start with these.
8.5.1

Stroke Rehabilitation

	Tables 1 and 9 summarize four reasonably well designed studies of adjunctive acupuncture in stroke rehabilitation. The results show consistently that if acupuncture is added to a standard care treatment regimen, the outcome is significantly better than the standard care treatment regimen alone, sometimes with significant cost reduction. This suggests a potential use of adjunctive acupuncture in the rehabilitation of stroke patients. Reviews of the use of acupuncture in stroke rehabilitation generally agree with these conclusions [33, 41, 61]. For additional studies see [63, 64].
	 SPECIAL_IMAGE-page0173_0000.svg-REPLACE_ME 
8.5.2

Addiction - Drug Dependence

	Tables 2 and 9 summarize four reasonably well designed studies of adjunctive acupuncture in the treatment of addiction. The studies included focus on alcohol, cocaine, and opiate dependence. The evidence in these three areas is variable and there are contradictory results in each. However, the treatment of drug dependence is a huge and very complex problem. To date, there are few effective standard care treatment options in each of these areas, making the use of adjunctive acupuncture treatment a viable option in many drug rehabilitation programs in the U. S. and Europe [ 16, 20]. There are also a number of large-scale studies underway or near completion in the U. S. The author worked on a large study for cocaine addiction in methadone-maintained patients at Yale University and was a scientific advisor to a larger six-center multisite study for cocaine addiction through Columbia University [59]. Preliminary results from the Yale study are very promising (Arthur Margolin, personal communication). Looking at the evidence so far, we can see quite promising results in the area of alcohol dependence, with some promising but contradictory evidence in the areas of cocaine and opiate dependence. The results suggest there is potential for the use of acupuncture in drug rehabilitation programs, but more research is needed. For additional studies see 17, 21, 46, 47, 67, 87, 88]. It is important to remember that acupuncture alone is not effective in treating drug dependence. The use of acupuncture should always be as an adjunct to a standard drug rehabilitation program with individual and group counseling [20]. It should also be noted that addiction treatment research is a particularly difficult area. There are many problems to be overcome before research can be performed successfully [27].
	 SPECIAL_IMAGE-page0176_0000.svg-REPLACE_ME 
8.5.3

Angina Pectoris

	Tables 3 and 9 summarize four controlled studies on the use of acupuncture in the treatment of angina pectoris. The results of the first two are contradictory [9, 13], but the possible benefits found in the first of these studies are reinforced by the results of Richter et al. [69]. Perhaps the most interesting results are those of the fourth, larger study [ 10]. Here, acupuncture was added into a novel treatment plan for patients with angina pectoris. While the comparison group was only a historical control (retrospective comparison of published data for a similar patient population) so that nonspecific effects were not at all controlled, the significant benefits found suggest that it may be undesirable or unnecessary to conduct only controlled studies with appropriate nonspecific controls in the treatment of angina pectoris. Subjective and objective improvements as well as cost reduction were very significant. It may be best to consider the use of acupuncture in the treatment of angina pectoris as part of an overall treatment plan, especially one that uses self-help procedures such as those recommended in the study (acupressure, stress reduction measures, relaxation-inducing measures, exercise recommendations, and dietary recommendations.) The results suggest a potential use of adjuvant acupuncture in the treatment of angina pectoris. For additional studies see [11, 12].
	 SPECIAL_IMAGE-page0179_0000.svg-REPLACE_ME 
8.5.4

Urology

	Tables 4 and 10 summarize four controlled studies on the use of acupuncture in the treatment of various urological problems, including lower urinary tract infection, kidney stone pain, incontinence in the elderly, and urgent incontinence with frequent urination and nocturia. There have also been a number of uncontrolled studies suggesting positive effects of acupuncture on bladder function and urinary problems [26, 66]. While the data regarding the efficacy of acupuncture in urology is not yet sufficient for clear conclusions, the few controlled studies in this area are suggestive of positive effects of acupuncture in urology, even in cases of recurrent lower urinary tract infections and kidney stone pain, notoriously one of the most painful conditions which may present to the emergency room of a hospital. Two of these studies used an acupuncture treatment versus standard treatment design and found that, while the acupuncture generally had similar, possibly somewhat better treatment effects, the side effects were markedly less in acupuncture treatment groups than in standard drug therapy groups [45, 48]. Clearly, more studies are necessary before conclusions can be drawn, but at present the current evidence is quite promising for the use of acupuncture in the treatment of urinary frequency, incontinence, and urgency, recurrent lower urinary tract infection, and renal colic.
	 SPECIAL_IMAGE-page0182_0000.svg-REPLACE_ME 
8.5.5

Obstetrics

	Tables 5 and 10 summarize five controlled clinical trials on the use of acupuncture during pregnancy and labor. In particular, the studies examined the efficacy of acupuncture on breech presentation and the duration of and preparation for labor. In general, one may conclude that these studies show a clear effect of acupuncture on the rate of turning of breech babies [25] and in the duration of labor and maturation of the uterus for labor [70]. The latter study by Romer et al. is particularly impressive. The sample size was very large, the methodology good, the assessments very good, and the results very clear for acupuncture, compared both to control acupuncture and to a "no additional treatment" group. This study will stimulate much more research in acupuncture and pregnancy. While more research needs to be done in these areas to confirm the findings, the results so far are very encouraging for the use of acupuncture on pregnant women with breech presentation around the 33rd week of pregnancy and in general for women around week 36 to improve preparation for labor and make the labor easier and quicker. Acupuncture is clearly indicated in these two areas. For additional studies see [23, 30, 51, 75, 80, 91].
	 SPECIAL_IMAGE-page0185_0000.svg-REPLACE_ME 
8.5.6

Gynecology

	Tables 6 and 10 summarize three controlled studies on the use of acupuncture for the gynecological problems of dysmenorrhea, female infertility, and menopausal hot flashes. There are clearly not enough studies in this area, but the results to date are somewhat promising. Acupuncture seems to be helpful for dysmenorrhea, which is supported by other, less well designed studies [79]. The results of acupuncture for female infertility are interesting but need replication. The study for menopausal hot flashes is excellent in many regards, with the exception that the so-called placebo acupuncture treatment, i.e., superficial needling at the same acupoints as those used in the treatment group, was actually a better form of therapy for this symptom than the "real acupuncture" [ 15]. The application of inadequate acupuncture treatment and/or inappropriate control acupuncture treatment is a common and major problem in the design and interpretation of clinical trials [ 14, 15, 73]. Overall, we see suggestive evidence for the use of acupuncture in gynecological problems.
	 SPECIAL_IMAGE-page0186_0000.svg-REPLACE_ME 
8.5.7

Mental Health

	Tables 7 and 11 summarize four controlled studies of the use of acupuncture in the treatment of mental health problems, three for depression and one for schizophrenia. The study by Allen et al. [1[ is perhaps the most interesting. It was a very well designed study, with clear results favoring acupuncture for depression. While the evidence for the three studies examining efficacy of acupuncture for depression is still not very large, it is important to note that Allen and colleagues are in the middle of a larger study exploring acupuncture for depression, and other research teams are examining this use of acupuncture, notably one in Australia (Im Quah-Smith, personal communication). Further, possible physiological mechanisms have been put forward that support the use of acupuncture in affective disorders such as depression [391. The evidence for the use of acupuncture in schizophrenia is still scant but raises interesting questions in this very difficult problem. Some supportive evidence can be found in uncontrolled case study reports [44[. Further evidence of possible efficacy can be found in the area of drug dependence treatment, where acupuncture has shown promising results in the treatment of schizophrenic patients (Michael Smith, personal communication).
	 SPECIAL_IMAGE-page0187_0000.svg-REPLACE_ME 
8.5.8

Male Sexual Problems

	Tables 8 and 11 summarize two studies on the use of acupuncture for sexual problems in men. Very little research has been done in this area. While neither study was welldesigned, both provide sufficient evidence to warrant further studies of higher quality in the areas of acupuncture for impotence and low sperm quality.
8.5.9

Xerostomia

	Tables 8 and 11 summarize two studies on the use of acupuncture for xerostomia, or dry mouth. Xerostomia can result secondary to problems like Sjogren's syndrome and radiation therapy for certain cancers. The two studies were performed by the same research team and provide some evidence of the efficacy of acupuncture in this difficult problem. However, the second trial has been criticized for a number of problems, including overuse of statistical tests, poor hypothesis testing, and possible problems with randomization [3]. Taking the two studies together, promising evidence can be seen indicating the possible use of acupuncture for the difficult problem of xerostomia. Further clinical research would be useful in this area.
	 SPECIAL_IMAGE-page0188_0000.svg-REPLACE_ME 
8.5.10

Raynaud's Syndrome

	Tables 8 and 11 also summarize one controlled study examining the effects of acupuncture on Raynaud's syndrome. Since the sample size is small and the study used only a "no treatment control" group, it should be considered only as a useful pilot study. The results suggest a possible benefit of acupuncture in the treatment of Raynaud's syndrome, but a larger, well-designed, controlled clinical trial is needed to answer the question of its efficacy.
	 SPECIAL_IMAGE-page0189_0000.svg-REPLACE_ME 
	 SPECIAL_IMAGE-page0190_0000.svg-REPLACE_ME 
	There are a number of other areas where research has been done and reviews have concluded that treatment efficacy is doubtful. These are not included in the tables but are briefly discussed here.
8.5.11

Weight Loss

	Edzard Ernst conducted a systematic review of controlled studies examining the effects of acupuncture/acupressure on weight loss [32]. His review concluded: "On balance, no clear picture emerges to show that acupuncture/acupressure is effective in reducing appetite or body weight." This conclusion generally agrees with that of Vincent and Richardson in 1987 [85]. The weight of evidence suggests that acupuncture is not effective as an appetite suppressant or for weight loss.
	 SPECIAL_IMAGE-page0191_0000.svg-REPLACE_ME 
8.5.12

Hearing Problems

	Acupuncture has been used for chronic auditory problems such as sensorineural deafness and tinnitus. A few studies have been done in this area, but results have been quite inconsistent, with at best only temporary improvement. In 1975, Taub reviewed the literature and concluded that acupuncture made no contribution for sensorineural deafness [74]. In 1987, Vincent and Richardson also reviewed the studies in this area and concluded that there appear to be some short-term benefits but no longterm benefit [85]. There have been significant problems in study design in this area. A more recent study investigating acupuncture for tinnitus found some transient effects but no positive long-term effects [78]. The weight of evidence suggests that acupuncture is not very effective for hearing problems such as those described here.
	 SPECIAL_IMAGE-page0192_0000.svg-REPLACE_ME 
8.6

Conclusions

	Acupuncture has been tested in a relatively broad range of medical problems. This brief review has examined a number of areas where research can be found but, in most cases, there is insufficient evidence to perform systematic reviews. We found either good or promising evidence of the efficacy of acupuncture in most of these areas but, at the same time, methodological problems that undermine interpretation of the results.
	The evidence for the use of acupuncture as an adjunctive therapy for stroke rehabilitation is increasing. While there are conflicting data about the use of acupuncture as an adjunctive treatment for addictions, the existing evidence shows enough promise to warrant continued examination. Evidence for the adjunctive use of acupuncture for angina pectoris is also quite promising, as it is in various urological and gynecological problems. Evidence for acupuncture in breech version and to prepare for and assist in labor is already strong, especially with the 1998 studies of Cardini and Weixin for breech version 125] and Romer et al. for labor 1701. Evidence that acupuncture can be used to treat depression is also mounting and quite promising. In the case of male sexual problems, xerostomia, and Raynaud's syndrome, the results are somewhat promising, but much more data is needed. Acupuncture's efficacy in weight loss and hearing problems is less convincing. Each of the areas examined needs more research, usually with better methodology. In some areas such as angina pectoris, stroke, and addiction, it appears useful to focus study design more on the use of acupuncture as an adjunctive therapy in comparison to standard therapy alone, rather than only the gold standard of placebo-controlled double blind research. It appears necessary to continue the debate about the selection of appropriate research methodologies for future acupuncture studies.
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	63. Naeser MA, Alexander MP Stiassny-Eder 1), Galler V, Hobbs J, Bachman 1) (1994) Acupuncture in the treatment of paralysis in chronic and acute stroke patients: Improvement correlated with specific CT scan lesion sites. Acup Electrother Res Int j 19:227-250
	64. Naeser MA, Alexander MP Stiassny-Eder D, Lannin LN, Bachman 1) (1994) Acupuncture in the treatment of hand paresis in chronic and acute stroke patients: Improvement observed in all cases. Clin Rehab 8:127-141
	65. Patel M, Gutzwiller F, Paccaud F, Marazzi A (1989) A meta-analysis of acupuncture for chronic pain. Int J Epidem 18:900-906
	66. Philp T, Shah PJR, Worth PHL (1988) Acupuncture in the treatment of bladder instability. Brit J Urol 61:490-493
	67. Rampes H, Pereira S, Mortimer A, Manoharan S, Knowles M (1997) Does electroacupuncture reduce craving for alcohol? A randomized controlled study. Complem Ther Med 5:19-26
	68. Richardson PH, Vincent CA (1986) Acupuncture for the treatment of pain: A review of evaluative research. Pain 24:15-40
	69. Richter A, Herlitz J, Hjalmarson A (1991) Effect of acupuncture in patients with angina pectoris. Euro Heart J 12:175-178
	70. Romer A, Weigel M, Zieger W, Melchert F (1998) Veranderungen von Cervixreife und Geburts- dauer nach geburtsvorbereitender Akupunkturherapie. In: Romer A (ed) Acupunkturtherapie in der Geburtshilfe and Frauenheilkunde. Hippocrates, Stuttgart
	71. Sallstrom S, Kjendahl A, Osten PE, Stanghelle JH, Borchgrevink CF (1996) Acupuncture in the treatment of stroke patients in the subacute stage: A randomized, controlled study. Complem Ther Med 4:193-197
	72. Siterman S, Eltes F, Wolfson V, Zabludovsky N, Bartoov B (1997) Effect of acupuncture on sperm parameters of males suffering from subfertility related to low sperm quality. Arch Androl 39:155-161
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	74. Taub HA (1975) Acupuncture and sensorineural hearing loss: A review. J Speech Hearing Disord 40:427-433
	75. Tempter C, Zeisler H, Heinzl H, Hefler L, Husslein P, Kainz CH (1998) Influence of acupuncture on maternal serum levels of interleukin-8, prostaglandin F (2-alpha), and beta-endorphin: A matched pair study. Obstet Gynecol 92:245-248
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  CHAPTER 9

  Beyond Numbers: Qualitative Research Methods 
 for Oriental Medicine

C. M. Cassidy

9.1

Introduction

	Qualitative research is the term given to the branch of scientific research that emphasizes the collection and study of perceptions and experiences - the "stories" - of living people. Stories are powerful. Some years ago, I was sitting in the treatment trailer at a city jail listening to women receiving acupuncture detoxification (detox) talk about their lives, their addictions, and their experiences of acupuncture care. All of it was interesting. But near the end of the visit, one woman uttered a few poignant words that encapsulated everyone's hopes and reminded the practitioners of their deep task: "I chose acupuncture because I figured if a needle got me into this mess in the first place, maybe a needle could get me out."
	Words can be needles, too. By gathering the thoughts and feelings of people - patients, practitioners, lawmakers, teachers, students - one can learn more about the "why" and "how" of people's preferences and decisions, the images that compel and the emotions that propel, than by any other method. Qualitative research encourages people to speak their lives, beliefs, dreams, and visions, their experiences and interpretations of events, their motivations. From their words comes a better understanding of "what matters" to those who speak. This is information that those who listen can put to work usefully to solve problems.
	This chapter introduces the basic ideas and methods of qualitative research for practitioners of oriental medicine. Because some qualitative techniques use skills already familiar to clinicians, office-based practitioners can easily adapt them to use in assessing elements of their own practice and in planning for survey research.
9.2

Qualitative Research Is Scientific

	There is a tendency among quantitative researchers to view "stories" as anecdotes - minor if interesting sidelights on the "real" stuff, that is, distributions expressed as statistical probabilities. Qualitative researchers take a rather different view, one which we must understand from the outset.
	The "anecdote" is a single story without context. It is used to make a specific point. The quotation that appears in the first paragraph above is anecdotal because it is segregated from the other data gathered that same day, on subsequent days in the same locale, and from other settings in which jailed women received detox acupuncture. Anecdotes are not scientific; at the same time, they are not worthless: they draw one's attention, help memory, provide imagery, succinctly summarize complexities, and often serve to "put a human face" on medicine. The fact is, everyone relishes a good anecdote.
	However, the focus of qualitative research is not on anecdote. Instead, like quantitative researchers, qualitative researchers apply the usual rules of science:
	- To gather and analyze information systematically
	- To do so with attention to minimizing bias
	- To achieve data that is accurate, valid, credible, and usable to answer questions, predict behaviors, and plan for the future.
	Qualitative research is as scientific as quantitative research, but it starts from different premises and demands different techniques for both data gathering and data analysis 1 1-3, S, 7, 16, 20]. Frequently, qualitative and quantitative methods are applied in the same research task. As might be expected, this is called "mixed qualitativequantitative" research.
9.3

Gathering Qualitative Data

9.3.1

Identifying the Research Question

	As in all research, the qualitative researcher first must identify an appropriate study question. The best uses of qualitative research are in finding out the parameters of a new subject (exploratory research) and gathering detail about the meanings of events. Table 1 compares the kinds of questions best asked of quantitative and qualitative research. Note that only qualitative and experimental laboratory research can answer the questions "why?" and "how?" - that is, provide explanations. Other research - archival, survey, clinical outcomes, and clinical trials research - provides rich descriptive data, including statistical distributions that define "who, what, where, when, how many, and how much" but cannot detail the linkages that explain behaviors. Therefore, if you are interested in why people do what they do - their perceptions and motivations - use qualitative research methods.
	 SPECIAL_IMAGE-page0199_0000.svg-REPLACE_ME 
	When very little is known about a topic, qualitative research is time and cost effective for finding out generally what people think is going on. Oriental medicine is full of such areas of mystery:
	- Does needle depth matter?
	- Do the patients of practitioners of TCM, Worsley Five Element, French Energetic, and Toyo Hari styles have significantly different experiences with acupuncture?
	- Are students at schools that provide a cultural context for Chinese medicine more secure in their knowledge afterwards than students from schools that do not?
	- What does it mean when practitioners claim to be "holistic" healers?
	- Are the concepts of "energy" and "qi" combined for American practitioners?
	- What factors help make for successful practitioners 5 years out of school?
	- What do qi gong practitioners experience when they "throw" qi?
	- What do patients understand about the theory of oriental medicine after a course of treatment?
	There are also many situations where it is useful simply to know what people perceive and interpret and what experiences they take away from an event, for example, acupuncture care. Such information can be used immediately to remedy fault lines in the design of an office or in the delivery of care, or it can be used to help create survey and clinical trials designs that accurately reflect the wants, values, and needs of research participants.
	To illustrate the latter use, suppose a group of practitioners in a large private clinic suspected that many of their clients were dissatisfied with their clinic experiences and wanted to identify points of strain in their receipt of oriental medical care. The practitioners could sit down and create a survey questionnaire containing questions concerning the waiting room, practitioners' behavior, attitudes toward needles, quality of parking, and so forth. Once a sufficiency of clients had ticked off answers on this survey form, the practitioners would receive data - quantitative data. But would these really answer the core question they hoped to ask? Perhaps not, for the questions the practitioners thought to ask might not cover the whole range of issues important to the patients. Something crucial might have been left out. In order to get at the clients' issues - which are after all what matter most if clients are showing signs of discomfort and distress - these practitioners must make it possible for the clients to tell them what is right and not so right with their clinic. How? - Ask them directly.
	To ask people directly is at the core of the qualitative method. It sounds so simple, but it is surprising how often research is designed in accord with researchers' assumptions, without direct knowledge of the client population. The classic approach is via in-depth interviews with a sample of the patients, the gathering of qualitative data. In our example, the practitioners could use the analyzed results of a series of interviews either to make immediate modifications in their office procedures or, if they wanted more data on a larger sample, to construct a high quality survey form that both reflected the clients' issues and phrased them in the clients' language. The quantitative data from this new questionnaire would more accurately report client issues (the technical term is "be more valid") and therefore could be more safely applied to making effective changes in clinic arrangements.
	A similar procedure is appropriate when, for example, an oriental medicine professional organization wants to survey members or a school wants to survey alumni: first collect a detailed, small scale qualitative sample and use the qualitative data later to create a large scale survey questionnaire to sample the whole membership. A questionnaire designed this way - with a firm understanding of the importance of knowing respondents' issues and reflecting their language habits - has (another technical term) high model fit validity. Validity is a measure of whether a piece of research gathers data that actually answers the research question asked'.  The model one wishes to fit, in this case, is the model of reality held by the respondent population. This is partly conscious and expressible, partly unconscious, which brings us to the next issue: how do you actually collect experiential data from people?
9.3.2

Direct Data Collection Techniques

	There are two ways to gather qualitative data, direct and indirect (Table 2). Direct methods help respondents talk about what they know "at the top of the mind." Indirect methods allow respondents to reveal what they don't realize they know - such as attitudes, assumptions, and logical structures that can markedly affect their responses to treatment, teaching, or practice.
	Although there are many other qualitative techniques, for our purposes only those listed in Table t will be described. The most popular direct methods are the oral interview, the written diary, and the case study. The focus group and written techniques are frequently used in mixed qualitative-quantitative research.
9.3.2.1

In-Depth Interviews

	The most important direct research method in qualitative research is the in-depth interview [12, 17). One interviewer (researcher) talks with one respondent about a fairly broad topic such as (with a patient) what experiences they have had with acupuncture or (with a practitioner or student) why they chose to study oriental medicine and how it is or is not rewarding. The interviewer prepares a short list of openended questions intended to allow respondents to describe their experiences and reflect on them. An open-ended question is one which sets a topic but does not lead the respondent to answer in any particular direction. For example, one might ask: "What made you decide to study acupuncture?" Because no answer is implied, respondents are free to "tell their story" as they wish.
	 SPECIAL_IMAGE-page0203_0000.svg-REPLACE_ME 
	Besides using open-ended questions, in-depth interviewers must develop another skill, which is to listen attentively, so-called active listening. After asking a main question, the interviewer tries not to interrupt. At most, he or she uses affirmative "hmmm" and "mm" or very short probe questions - "Yes?" "Oh?...," or "What happened next?" - to keep the respondent talking. Another technique is to reflect the respondent's words back to him. To illustrate these points, here are two brief excerpts taken from interviews with acupuncture patients at a school clinic:
	Interviewer: What helped you make the final decision to come [for acupuncture care]?
	Respondent: Honestly?
	1: Honestly.
	R: It was the discount on the money.
	I: Can you tell me about some of the bad stuff?
	R: Well, the very first treatment they did on me, I cried through the whole thing. I didn't really want to come back. But ]practitioner's name] assured me the next one wouldn't be as bad [respondent laughs] - and it wasn't. It was better. The next one, better. And each time I came, I felt different.
	I: In what way?
	R: In a good way. I felt better in a good way.
	I: What was that? What's your "better in a good way?"
	R: I guess the best way to describe it is I feel more grounded and, before, I didn't.
	Practitioners will recognize that many of the skills of the clinical interview are transferable to the informational interview. However, there is a mistake clinicians can easily make and must avoid: transforming an informational interview into a medical interview. Note that this may be especially troublesome if the respondent is in fact one of the interviewer's patients. Thus, clinicians must keep very clear throughout research interviews that they are "wearing a researcher hat," not a practitioner hat. The following excerpt illustrates this mistake. As we begin, the interviewer functions as researcher, but by the second question he has stepped into practitioner mode. Rather than gathering detail on the concepts broached by the respondent - the idea that all things are interrelated - he is gathering detail on the patient's pain:
	I: What is your expectation of acupuncture?
	R: I learned from physical therapy that everything can affect everything else...so I'm open to the idea that just tension or stress in one part of the body can trigger something somewhere else and bring down a whole raft of symptoms. For example, my teeth ache, but [the dentist] says there's nothing wrong with my teeth.
	L: When you talk about them aching, what is the sensation in your body?
	R: It's just the teeth themselves ache. It's not like a toothache from decay.
	I: It's ongoing and you feel it all different times of the day?
	R: All different times of the day. And then also, my life's gone down the drain, emotionally, socially, everything else.
	I: Due to these complications?
	R: Yes. Too many times you find out who your friends really are-
	I: Has that been hard, giving up the relationship?
	This excerpt also illustrates another common error in interviews, that of putting words into the respondent's mouth. This occurs in this interview in the third interviewer remark. Here he suggests to the respondent that the pain is ongoing and his teeth ache at all times of the day. These are not ideas that the respondent has previously stated. As clinicians, we can understand that this interviewer (functioning as clinician) is searching for symptom patterns that matter in oriental medicine; in the process, however, he is preventing the respondent from telling his own story in his own words. Qualitative interviewers must allow respondents to speak for themselves. Indeed, as far as possible, the qualitative interviewer should become virtually invisible to the respondent.
	This idea of "invisibility" implies one more extremely important feature of the indepth interview: it must be nonjudgmental in tone. The interviewer's task is to gather information, not to guide, correct, or offer advice to the respondent. This point is extremely important: the informational interview is not a clinical interview. The qualitative interviewer stands in a position of open listening, of learning; he or she must not stand in the position of expert. Sometimes this requirement may be difficult for a clinician to heed, but it is necessary if one wishes to do research rather than practice one's medicine.
	Is this unfair, unfeeling? Does it sound like the bogey of the manipulative scientist in the white coat? It shouldn't. The fact is, when people volunteer to be interviewed, there is no expectation that the quality of their beliefs or health will be called into question. The interviewer and respondent establish a bond of trust, but it is a different bond than that between clinician and patient. In the qualitative interview, the researcher's task is to pay attention, listen, and be an open well into which the respondent can pour the water of his/her life. Interestingly, most respondents report that they thoroughly enjoy being the focus of in-depth interviews. In many cases, an interview is the first time that they have felt really heard, the first time they could "tell it like it is" to someone who would not interrupt and correct and advise. This is rewarding to the respondent; it is also rewarding to the interviewer!
	In-depth interviews are long - 45 to 90 minutes is not unusual - and repeated interviews with the same respondent may be arranged. It is wise to audiotape all lengthy interviews. You must receive the respondent's permission to interview and to tape-record. Use a brief written consent form to explain the uses that will be made of the data. Additionally, after you turn on the tape recorder, ask the respondent to answer out loud with a clear "yes" to your first question, "Is it all right with you if I tape-record this interview?" Assure the respondent that you will turn off the tape recorder if he or she wishes to discuss something private. You may take notes during the interview - as long as you keep good eye contact with your interviewee - but stop writing if the respondent indicates a wish to speak privately.
	Needless to say, a single interview does not a research project make! In order to understand a topic thoroughly, the researcher must perform in-depth interviews with a number of people. As in quantitative research, qualitative researchers develop an appropriate sampling frame to select the interviewees, for example, by sex, age, location, specialty, length of experience - whatever is most relevant to the research issue.
	They are also concerned with sample size. However, in contrast to quantitative research, the goal is not "large" samples, but samples that best reveal all facets of the issue. Therefore, qualitative researchers typically do not set the sample size before beginning research. Instead, they let the research itself guide sample size. Suppose the task were to find out the experiences of practitioners in treating migraine-type headaches in the Portland, Oregon region. The researcher would begin by identifying as many practitioners as possible who are known to emphasize the care of headaches. When interviewing these specialists, the researcher would ask if the respondent can recommend anyone else who is well-known for treating migraine headaches. By this method, the researcher would gradually locate all the people regionally who have special interest or expertise with headaches.
	The researcher might interview all these people or might sample among them. For example, one might wish to know the various explanations practitioners give for the causes of migraine-type headaches. In this case, one would continue interviewing until explanations kept recurring and could then say with some certitude that there are, for example, ten explanations of cause for migraine-type headaches among the study population, of which four are widely shared (mentioned by nearly everyone in the sample), four are shared by several respondents, and two are mentioned by only one respondent each. This information is interesting in itself. It could also be used secondarily to help guide the design of a survey instrument, if the researcher wished to expand his research but knew that he could not do nationwide in-depth interviews. In this case, he would be sure to include the four most popular options on the survey instrument and would add a space labeled "other" so respondents could write in other explanations which might or might not be the same as those mentioned in Portland.
	Note that with in-depth interviews, the rules of science listed above are followed. Data collection is systematic: there are a specific research question, sampling frame, and sample size, and there are formal parameters to the interview process. There is attention to minimizing bias: the interviewer adopts a special stance and uses special techniques to ensure that the ideas and experiences of the respondent are revealed as accurately and completely as possible - that is, validly and credibly. Once analyzed, such data can be used to offer interpretation and explanation, predict behaviors, and plan for the future.
9.3.2.2

Focus-Group Interview

	In this form of interview, several people are interviewed at once [12, 20]. A main interviewer asks the questions and an assistant runs tapes, observes people as they answer, and "spells" the main interviewer when necessary. This approach is appropriate when the topic under study is broad and the answers needed are relatively easy for people to discuss publicly. Groups are formed that share important characteristics - such as age and sex - plus the focus issue. The group of jailed women receiving acupuncture detox mentioned at the beginning of this paper were interviewed in an informal focus-group manner.
	Focus-group interviewing can be carried out as a qualitative or a quantitative procedure. As a qualitative procedure, the interviewing goals - and most of the methods - are the same as for in-depth interviews: researchers want to find out what meanings are contained in an issue. In the quantitative procedure, interviewers use a predetermined closed-ended set of questions and carry out what is essentially an oral opinion survey. This approach is popular with those who measure attitudes to new products, politicians, or public issues.
	Some differences are introduced by having many people involved at once. For example, trust must now be established not merely between two people but among many. This is best achieved by being sure the sample membership shares similarities and by a lead interviewer who is skilled at helping people establish rapport. It is also important to establish ground rules for the respondents from the outset - for example, that although they may respond to others' comments and should express their opinions, they must not be harshly judgmental nor should they give advice.
9.3.2.3

Keeping a Diary or journal

	In this method, participants in research track their attitudes and experiences by writing about them every day, generally at home 18, 201. In its simplest form, the diary is completely open-ended, with respondents simply asked to describe "whatever" about their lives with regard to, say, receiving or studying acupuncture care. Commonly, diaries are added to clinical trials or outcome studies of specific topics and used to gauge participant perception and interpretation of test interventions. In this case, respondents still talk about their lives, but this time with a focus on the test issue. For example, if one were comparing the recovery of stroke patients, some of whom received standard care and some of whom received standard care plus acupuncture, one might use the diary method to find out how participants perceive their progress. One could also use in-depth interviews in this situation, but the diary has the advantage of tracking change over time and not requiring as much time investment by the researchers.
	Note that the word "diary" is applied in two very different situations. The true diary is a qualitative method in which the writer is simply asked to report "what is happening" with regard to some issue. A quantitative procedure version of the diary is not open-ended and instead resembles a survey form that one must fill out repeatedly at specified intervals.
9.3.2.4

Open-Ended Response on a Survey Questionnaire

	In this example of mixed quantitative-qualitative research, a quantitative survey questionnaire includes space for personal responses. This can be done by adding white space at the end of forced-choice survey questions or it can be done by providing space at the end of the survey and inviting respondents to add their own comments. Here's an example of the first type, adding white space after a forced-choice question:
	Many different methods of paying for acupuncture care have been considered. Which of the Jollowing payment options would you prefer, if you could choose any of them? (Select one).
	Insurance that covers 80 % of my bill and does not limit my choice of-acupuncturists but does limit the number of times I can visit my acupuncturist.
	Membership in a preferred provider organization that limits my choice of acupuncturists but covers all costs except for a small copayment.
	Membership in a referral organization that offers a select group of acupuncturists and a 20 % discount on care.
	The way it is for most of us right now. I choose my acupuncturist and pay directly for my care.
	Please use the space below to explain briefly your choice from the above list.
9.3.2.5

Case Study, Case Series

	In a case study, the researcher examines a single example of the issue in extreme detail [22]. This form of study is very popular in medicine, where it is often called a case history; it is a relatively easy entree to research for clinicians. Case studies usually describe and analyze puzzling clinical situations and report how the practitioners handled and often solved them [ 18]. In the sense that they describe single events, case studies are like extended anecdotes. However, when well-done, case studies can meet scientific criteria for systematic collection and analysis of data. They are useful to other practitioners and may even spur focused research.
	At the same time, the danger always exists in case studies that the practitioner misinterprets the event or his part in it. Thus, when careful practitioners think they've found a novel way to help people with a distinct pattern of malfunction, they will attempt to collect a whole series of similar cases. Each must be collected in much the same way - reporting the symptomatology, previous care, test care, response of the patient, and how long the improvement lasted. The researcher then tries to draw conclusions from the massed data and tries to make generalizations linking the specific cases. When convincing, case series serve two important functions: they allow a researchable hypothesis to emerge from clinical data and they provide pilot data for writing proposals to examine the hypothesis via a quantitative design, such as a clinical trials design. Thus, case series - a qualitative technique - are often used to fuel subsequent quantitative research.
9.3.3

Indirect Data Collection Techniques

	The techniques summarized above emphasize the collection of information that the respondent can fairly easily think about and verbalize, that is, information that is consciously known. It is also possible to gather information that respondents do not know consciously or do not realize they know. Suppose you want to know what factors in patient beliefs affect the probability that they will recover from illness. Asking a direct question such as: "Do you want to get well?" is likely to provoke a knee-jerk response: "Of course!" However, you observe that some people who answer this way do get well while others linger in illness. Supposing you have already deleted "easy" causes such as different degrees of severity, what explains such differences? Research has shown that it is often differences in unconscious values, beliefs, and logical structures [21].
	To gather information on unconscious knowledge, researchers have developed a set of techniques called projective tests. There are many. In this chapter, I will describe just one which is simple enough for office-based practitioners to use in concert with in-depth interviews. This is called the card-sort method [20]. Most people respond to it as a game and enjoy it.
	In this method, the researcher prepares a set of cards on each of which is printed a single word or short phrase; each card is also numbered. The respondent is asked to sort the cards into stacks that "make sense." The researcher records the content of each stack by recording the numbers and then asks the respondent to "name" the stack and to explain why the cards that are in it go together. The respondent may also be asked to sort within a stack, for example, to sort disorders by severity. Once such data has been gathered from a sample of respondents, the researcher can analyze it by frequency (a quantitative function) and by content (a qualitative function).
	Here is a simple example. Suppose a researcher wrote the names of acupuncture points on cards and asked practitioners to sort them "in any way that makes most sense to you"
	- The set: 51. 16, SI.17, Du15, Du16, Du26, Lu.11, Sp.l, Sp.6.
	- Respondent 1 sorts by meridians: SI.16, 17; Du 15, 16, 26; Lu.l l; Sp.l, 6.
	- Respondent 2 sorts by location: shoulder and neck SI.16, 17, Du 15, 16; face I)u 26; arm Lu.11; leg Sp. 1, 6.
	- Respondent 3 sorts by specialty: window of the sky point SI.16, 17, Du 15, 16; ghost point Du 26, Lu.11, Sp.1; three yin leg point Sp.6.
	Note that all these sorts are "correct," although correctness is not the issue. Instead, we are interested in the different ways that people choose to organize data. Such differences could have clinical or other significance.
	In a real example that was part of a team effort to remedy inadequacies in a national questionnaire, I wrote terms descriptive of "mental illness" on a set of 50 cards and asked respondents to a survey of "attitudes to mental illness" to sort them into stacks. They were given no further guidance, although the task I'd been given as researcher was to assess public attitudes to five common conditions including "depression." All respondents did, in fact, create stacks of cards containing words like "blue," "down," "depressed," "sad," and so forth. The fact that they selected the same words out of 50 means that all respondents perceived certain sensations as belonging together, forming a pattern. However, only one of 16 respondents used the psychologists' term and named the stack "depression" All the others used different descriptors such as "this is a person who doesn't feel too good about himself."
	When respondents were asked to sort within the stack for severity, they revealed unconscious beliefs that were novel to psychology: that most words relating to the psychologists' construct "depression" were not considered pathological by respondents (although they were by psychologists) and that the adjective "depressed" was considered much less serious a condition than the noun "depression" No one could have verbalized these points individually, but the card-sort method allowed unconscious knowledge to "speak" and (in this case) showed that it is similarly framed among the people sampled. Additionally - and here we arrive at an example of qualitative research providing explanations that quantitative methods cannot provide - the data helped explain the rather large gap between public behavior around "depression" symptoms and the perception by psychologists that "people don't come for treatment soon enough." According to the card-sort data, this is at least partly because they do not interpret the symptoms as pathological nearly as soon as psychologists do.
	These data also illustrate how the language of questions may inadvertently mislead researchers: a change such as that from adjective to noun in the questions below may mean that questions are interpreted very differently by respondents:
	In the last 3 weeks, how often have you experienced a depressed mood?
	In the last 3 weeks, how often have you been depressed?
	The card-sort technique is relatively easy to develop and respondents are often surprised and fascinated by the decisions they find themselves making. If they are encouraged to verbalize their processing of the card sort, the researcher may gain rich additional material for an in-depth interview.
9.3.4

Data Analysis Techniques

	In all research, one must first gather data, then analyze and interpret it. In quantitative research, the data collection process is usually more time-consuming than analysis; the reverse is true of qualitative research.
	In quantitative research, a limited number of possible answers are provided. This means that computer programs can easily manage them and statistical programs can easily count responses and show distributions of the data points. With qualitative research, in contrast, respondents use their own words to talk about issues in ways that are generally not predictable ahead of time. The analytic task, then, is not to count responses but to study the words so as to identify distinctive themes and shared perceptions among the respondents [2, 11, 19]. For example, when some people say "acupuncture makes me feel more grounded," do they mean much the same thing as those who say "acupuncture makes me feel more centered?" This process of analyzing the verbal, metaphorical, thematic, and other content of qualitative data is formally called content analysis. Content analysis often suggests that there are other issues worth pursuing; in this case, one may apply other analytic methods such as cognitive mapping, an illustration of which is given below.
9.3.4.1

Content Analysis

	Content analysis can often be done by hand. This is appropriate if the data set is quite small - for example, 30 or fewer respondents. However, if one is working with a large data set, nowadays it is much easier to use one of several qualitative analysis software packages on the market. In either case, the first step is to transcribe the interview tapes or written material from survey questionnaires or diaries into typed or word processed form so that they can be printed out and made easy to read. This unanalyzed data is called raw data.
	In the next step, the researcher reads the material - usually several times - to "get a feel" for its overall content. At this point, he is trying to find ways to analyze the data that will accurately reflect what has been said. For example, when people are asked "What has acupuncture been like for you?" they may answer by describing:
	1. How their health has changed
	2. What their practitioner is like
	3. What they think about the health care they received before acupuncture
	4. How their relationship to their spouse, children, job, or school has changed
	5. How their attitudes to life have changed
	A given person may discuss several of these themes; others may focus on just one. Some people speak poetically, using many metaphors and much imagery; others speak emotionally, yet others analytically. Some laugh while they describe their experiences, others weep. Some use strong language. As the researcher studies the raw data, he must decide which of the many issues and values are actually relevant to the research. Is it worth studying the metaphors people use? Does it matter if one person cries and another laughs? Additionally, the researcher must decide how to "cut" the data - one type of cut is shown by the five categories above.
	Supposing our researcher decides to use these five categories. He can now use a software program to help with the analysis. Most of the programs work more or less in the same fashion:
	The researcher moves the raw data from the word processing program into the qualitative analysis program, using identifiers as specified by the program. He then reads through the material, marking the themes as they appear, again according to the format of the particular software program. Once the themes are marked, the program can capture each theme with identifiers and print them out together. Now every instance of any theme, such as "practitioner description," is centralized in one file and can be printed out for further study.
	Such a treated theme is now much easier to study. Usually it rewards further subdivision, for example, descriptions featuring particular words or images: practitioner as genuine, caring or loving, skilled, knowledgeable, insightful, or trustworthy. In each case, negative descriptors are also recorded, that is: practitioner as untrustworthy, uncaring, and so forth.
	Now notice that one can make a count of images at this point - one can say, for example, how many times practitioners are described as genuine. However, the resulting number is not a valid indicator of how often acupuncture practitioners are viewed as genuine by patients, because this was not the question asked. What it actually measures is how often respondents thought to use the word "genuine" when describing their practitioner. And the reasons for thinking to use this word are potentially legion. For example, it could be a popular word in a particular region, while in other regions people prefer other terms such as "trustworthy." In a real case, I found that patients in two sites referred to their acupuncturist as "doctor," while in other sites patients used terms like "guide," "friend;" and "partner." Was there a major difference in perception of practitioners going on between sites? The answer was no; in the two sites where "doctor" was used, the practitioner held a doctoral degree; in the other sites, the practitioners did not ]6].
	In sum, when reporting frequencies of themes or imagery in qualitative research, researchers must avoid statistical formulations ("10% of respondents said..."), and instead use appropriate relativistic language: many, a minority, frequently, generally, rarely. In the context of qualitative research, such terms are not vague; they are accurate because the research set out to find patterns and perceptions, not frequencies.
9.3.4.2

Interpretation

	Notice that qualitative, similar to quantitative, research is heavily dependent on researcher interpretation. This means that the researcher must know as much as possible about the vagaries of interpretation and his or her own assumptive habits. This topic is developed in many methods texts, e.g., Bernard 1998 [2]. An example of (almost) letting one's own issues or hypotheses color the interpretation was mentioned above ("I wonder if practitioners called 'doctor' are authoritarian?"). The solution was also mentioned: first try to find an explanation within the data by going back to the source.
	This example signposts an important "rule" of scientific method (often called Occam's Razor): seek the simpler answer, because it is likely to be more trustworthy. In short, do not develop unnecessarily complex interpretations.
9.3.5

Data from a Qualitative Study of Oriental Medicine Patients

	Several qualitative studies of oriental medicine patients have been published. For example, Martha Hare studied the design of acupuncture health care delivery in private and public (including detox) clinics in New York City [ 13, 14]. Mitra Emad richly analyzed patient and practitioner experiences and perceptions [10] and discussed the meaning of pain during acupuncture needling [9]. Several similar studies are ongoing as of this writing.
	To provide readers with an on-the-ground example of qualitative research, I will describe data and details of the logic of data collection and analysis from my own survey of Chinese medicine patients in six private acupuncture clinics in five states (for the complete report, see [6]). As we move through this section, notice that raw data become increasingly refined and abstracted - the proper process of science - and that, at the end, some highly practical generalizations emerge, each of which is based solidly on data from the survey.
9.3.6

Developing the Survey Questionnaire

	With the intention of developing a quantitative survey questionnaire with high model fit validity, the study began with a preliminary qualitative research step: we performed in-depth interviews with 60 present and former patients of Chinese medicine. Each was asked six open-ended questions; all interviews were audiotaped. The tapes were transcribed and their content analyzed to identify issues important to respondents. These were used to develop questions about, for example, reasons for selecting acupuncture, attitudes to practitioners, presenting or chief complaints, changes in health in the presence of acupuncture, how relevant they thought acupuncture was in explaining their health improvements, how cost effective they thought acupuncture was, and so on. Practitioners and selected patients were invited to critique the questionnaire that emerged from this qualitative analytic process. (Normally, during this phase of questionnaire development, one would also study existing questionnaires designed to survey similar populations; but with Chinese medicine this is rarely possible, since so little survey research has been performed.)
	After developing a questionnaire that reflected the language and issues of patients and also satisfied practitioners, we performed two pilot tests. These test not only the questionnaire but the survey process; they are used to identify weaknesses in design. Adjustments were made in response to the pilot results and finally the pretested, mixed qualitative-quantitative questionnaire survey was run in six clinics that met predefined criteria for "large client population size." The survey received 575 responses, including 460 questionnaires that contained written or qualitative material.
9.3.7

Analyzing the Qualitative Data

	The quantitative and qualitative data from this survey were separately analyzed using statistical, word processing, and qualitative analysis software, as appropriate. Here I will discuss only the qualitative survey segment, specifically the search for themes in the handwritten responses to an open-ended final question inviting respondents to discuss their experiences with Chinese medicine.
	1. After transcribing the handwritten responses into the word processor, I printed them out and began to read and reread them, the first step in content analysis. The task is to know the material well enough to identify which themes best describe the material. I chose to list two types of themes separately, those that the respondents themselves identified and those that I felt emerged organically from their responses, such as popular metaphors about the body or being.
	2. Eventually, I identified five respondent-identified themes. Chinese medicine (as practiced in these clinics):
	a. Relieves symptoms and improves function.
	b. Improves physiological coping or adaptive ability.
	c. Improves psychosocial coping or adaptive ability.
	d. Involves a close patient-practitioner relationship.
	e. Treats the "whole" body/mind/spirit/social person.
	As you see, these themes are abstract: no respondents used exactly these words in writing about their experiences nor, had I asked directly, would anyone have said: "Oh yes, my experience can be broken down into the following themes...:.
	In short, I used the specific - stories - to abstract and study larger issues. I used individual accounts to identify commonalities that matter in the delivery of health care. No statistical analysis was involved, but the result is similar to what one would receive from quantitative analysis: general findings that can be applied to describe why American patients select and appreciate acupuncture care. In addition, the analysis allowed me to examine some broader issues, especially why Chinese medicine as framed in the U. S. fulfills many of the characteristics of the low-tech, low-cost, highrelational "new" medicine that health care planners wish to see emerge.
	Within each of the major themes were subthemes for which I could adduce evidence - that is, provide the words of respondents. For example, one subtheme within Theme I was "decreases the frequency, intensity, or duration of chronic complaints." Comments that sounded this message were frequent; one example reads: "Acupuncture makes the pain go away part of the time and each time staves it off for longer amounts of time. Soon I hope to be pain-free." No other respondent, of course, spoke exactly like this; qualitative researchers must pay attention to the content of each sentence to identify when respondents are sounding a particular analytic theme. Notice how different this situation is from that in quantitative research, where a forcedchoice question might ask respondents to say how much they agreed with a set phrase, such as "With acupuncture my pain is less severe" In the latter case, respondents can reveal degrees of acceptance of a question put to them by researchers, but they cannot reveal their own issues, put their own "spin" on issues, or talk about their hopes and fears ("Soon I hope to be pain-free").
9.3.8

Cognitive Mapping

	Certain words appeared in so many respondents' stories that it was obvious that these words were especially important to people in trying to express their relationship to Chinese medicine. I decided to follow up on these words to explore whether the ideas behind Chinese medicine had penetrated to patients. For example, Theme 3 - Chinese medicine improves psychosocial coping or adaptive ability - contained a popular subtheme which I called "engenders a sense of wholeness, balance, centeredness, well-being." Were these words and similar ones like "calm" and "grounded" all describing much the same response to Chinese medicine? With what other terms were these words associated? Specifically, were they associated with Chinese medicine terms like qi or its popular transfiguration as "energy"?
	To find out, I carried out an analytic procedure - not very difficult - called cognitive mapping (19]. In this procedure, you identify cue words that appear in many responses. You then use a simple "find" function in a word processing program to count how often these words occur. Using a qualitative analysis program, you can also print out the cue words with the two preceding and succeeding lines of type. You now begin to map: for example, how often does a "self-awareness/wholeness" word (calm, peaceful, centered, grounded, whole...) occur within two lines of a "Chinese medicine" word (qi, shen, yang, deficiency, sedate...), an "energy" cue word, or a "stress" cue word? Basically, you simply find all instances in which categories of cue words occur together and count them. (Notice that quantitative data is emerging from this qualitative analytic method.) The map consists of stating how close one set is to the next.
	In the present case, I found some surprising results: the strongest association was between self-awareness/holism words and stress words - when cue words occurred together, 40% of the time it was these two kinds together; the second strongest link was between "energy" and "self-awareness" (21.5 % of sample). There were, however, very few links between "Chinese medicine" and any other category, including "energy."
	What was Ito make of this map? First of all, it was clear that respondents were not using the language of Chinese medicine to describe their experiences. In fact, only seven used any language relating to Chinese medicine theory and not even one of the 460 respondents used the cue word qi. On the other hand, a majority of respondents used words redolent of the language and concepts of holism. In fact, what they were saying was "this thing called Chinese medicine delivers holistic care and allows me to convert stress to self-awareness/wholeness."
	Based on such information, one could argue that acupuncturists and herbalists are doing a poor job of teaching their clients the explanatory model of oriental medicine. Other qualitative data - specifically, the fact that respondents claimed that their practitioners were good teachers - suggested this is not the best explanation. Another possibility was that practitioners have successfully translated the oriental medicine idiom into an acceptable English language idiom featuring words such as stress, energy, and balance. This is the interpretation I chose. Such words are also used by practitioners of other alternative medical practices and are abroad in the society whenever people discuss the construct called "holism." Thus, based on story content, word use and cognitive mapping, I concluded that it appears that many consumers of Chinese medicine are purchasing not an exotic Chinese philosophy or theory but a home-grown holism.
	From this example, readers can understand not only the technique of cognitive mapping but also see how words and their patterns and the contents of handwritten or oral "stories" can be studied and abstracted to create generalizations. But of what use is it to know that American consumers are purchasing holism more than Chinese medicine per se? Actually, it has several practical applications. Let me quote from the end of the article:
	"...the present study is important not only because it reveals patient perceptions and values, but also because it defines theoretical components of holism, shows how these might be actualized in practice, and then goes on to show that, in at least one case, a large sample of patients are receiving care that they experience and define as holistic. This is all the more remarkable as these patients are located in clinics that are geographically remote from each other. What links the clinics, then, is not location or experience, but a construct called 'Chinese medicine' - and this medicine, whatever the case elsewhere in the world, or even in other American settings, emerges in this setting as holistic."
	"This study, then, can serve as a model not only of what holism feels like to patients, but also of what it might look like in practice. And what it 'looks like' is very much what health care philosophers and planners are seeking: a low-tech, high-relationship practice with users experiencing both relief of presenting complaints and expanded effects of care including improved self-reliance, plus high satisfaction with the care and the experience."
9.4

Qualitative Research Needs in Oriental Medicine

	I hope that this discussion and the illustrations have piqued the interest of readers. Clearly, some aspects of qualitative research lend themselves to use by acupuncture practitioners, even if they are not formally trained in research methods. I particularly recommend the in-depth interview, the card-sort technique, using initial qualitative research to develop quantitative survey questionnaires, and using qualitative diaries during clinical outcomes and trials research.
	Anyone deciding to do such research is also well-advised to consult a specialist to check whether his or her plans meet the formal criteria for good qualitative research. If you don't know a qualitative researcher, contact a nearby university or college for help. Look for qualitative specialists especially in anthropology, sociology, and nursing departments.
	Here is a sampling of appropriate questions that will reward qualitative research - it's easy to add many more - and notice that all are pragmatic:
	1. What is most meaningful to experienced practitioners about their work?
	2. What features of their education reaffirm student decisions to stay in school and which make them want to drop out of the field?
	3. What characteristics of acupuncture practitioners are most valued by acupuncture patients?
	4. What messages from practitioners are most rewarding to patients and which are least rewarding?
	5. How can practitioners speak so as best to motivate their patients to make needed changes in lifestyle?
	6. What easily identifiable features make patients most or least likely to respond to acupuncture care?
	7. How would patients like most to pay for their care? What is the reasoning behind their choice?
	8. What practitioner characteristics are most common in those who have rewarding full-time practices 5 and 10 years after graduating from school, respectively? Can success of incoming students be predicted by these parameters?
	9. Does needle depth matter?
	10. Do the patients of practitioners of TCM, Worsley Five Element, French Energetic, and Toyo Hari styles have significantly different experiences with acupuncture?
	11. Are students at schools that provide a cultural context for Chinese medicine more secure in their knowledge afterwards than students from schools that do not?
	12. What does it mean when practitioners claim to be "holistic" healers?
	13. What is the relationship between the concepts of "energy" and "qi" for American practitioners?
	14. What do qi gong practitioners experience when they "throw" qi?
	15. What do patients understand about the theory of oriental medicine after a course of treatment?
	16. What do practitioners say about the "intentionality" of their care?
9.5

Uses of Qualitative Research

	In this chapter, I have defined qualitative research and given examples of its use and advantages in a number of situations. Still, qualitative research remains the "mystery stepchild" in the minds of many researchers and in the public mind. Why is this? A full answer is too complicated for this chapter, but it is worth mentioning that the issue is partly one of cultural values and perception.
	When asking "Does oriental medicine work?" it is common for people to focus on comparative clinical questions such as "Is acupuncture as effective as standard care in the treatment of a given condition?" This is the familiar biomedical formulation and the sort of topic most likely to receive funding since the biomedical framework remains sociopolitically dominant. However, this kind of question addresses only a fraction of what needs attention in the field of oriental medicine and it can provide only a fraction of the information needed to answer the "Does it work?" question. Other issues that help answer the question include those concerning (a) within-thefield issues such as the significance of differing needle depths, (b) physiological mechanisms, (c) demographic and epidemiological distributions, and d) people's motivations for seeking and continuing the use or practice of oriental medicine. Each of these issues is right for research and it is in the last field listed where qualitative research will reap its greatest harvest. This is because, no matter how much we may know about the mechanism or comparative effectiveness of oriental medical care, if people won't buy it, the other information becomes insignificant.
	Don't take this idea of "buying" too literally. We use this term literally to speak of dollars and cents; we also use it metaphorically to speak of credibility. Credibility is built primarily through - here is where the other shoe drops - telling stories. Indeed, to reach the mass of people, the number-laden results of quantitative research must be translated into narrative or "story" form. It is through narrative that people become convinced to study the field, create laws that support it, fund research for it, and become acupuncture patients.
	Thus, the telling of stories - if they are built upon a base of properly collected and well-analyzed data - is at the core of all communication about oriental medicine.
9.6

Closing Remarks

	Qualitative research is a powerful method - indeed the only method - for gathering the "stories" of people's lives and assembling information on the assumptions and beliefs that reveal motivations and explain people's behaviors. When we know what has meaning for others, we can put this information to work to solve daily problems from the local (e.g., how to design clinics to enhance patient recovery, how to minimize student dropout in acupuncture schools) to the general (how the theory of Chinese medicine translates into the American setting, why patients find oriental medical care satisfying).
	Qualitative research lends itself to use by practitioners in their offices. However, to use the techniques described, clinicians must clearly distinguish their research task from their medical task and develop systematic designs for data collection. This chapter has introduced some basic techniques, warned about pitfalls, and proposed ideas for needed qualitative research in the field of Chinese medicine. I hope that readers will pursue some of the ideas proposed in this chapter and develop their own ideas putting qualitative methods to work.
References

	1. Bernard HR (1993) Research methods in cultural anthropology. Second edn. Sage Publications, Thousand Oaks
	2. Bernard HR (1998) Handbook of methods in cultural anthropology. Altamira Press, Thousand Oaks
	3. Brink PJ, Wood MJ (1988) Basic steps in planning nursing research, from question to proposal. Third edn. Jones and Bartlett Publ, Boston
	4. Cassidy C (1995) Social science methods in alternative medicine research. J Altern Compl Med 1:19-42
	5. Cassidy CM (1994) Unraveling the ball of string: Reality, paradigms, and the study of alternative medicine. Advances. J Mind-Body Med 10:5-31
	6. Cassidy CM (1998) Chinese medicine users in the United States, Parts I and 2. J Altern Compl Med 4:17-27, 189-202
	7. Creswell J (1994) Research design, qualitative and quantitative approaches. Sage Publications, Thousand Oaks
	8. Denzin NK, Lincoln YS (1994) Handbook of Qualitative Research. Sage Publications, Thousand Oaks
	9. Emad M (1994) Does acupuncture hurt? Cultural shifts in experience of pain. Proc Soc Acupunct Res 2:129-140
	10. Emad M (1998) Feeling the qi: Emergent bodies and disclosive fields in American appropriations of acupuncture. Dissertation available from Univ Michigan Microfilms, Ann Arbor
	11. Feldman MS (1995) Strategies for interpreting qualitative data. Sage Publications, Thousand Oaks
	12. Fontana A, Frey J (1994) Interviewing, the art of science. In: Denzin NK, Lincoln YS (eds) Handbook of qualitative research. Sage Publications, Thousand Oaks, pp.361-376
	13. Hare M (1992) East-Asian medicine among non-Asian New Yorkers: A study in transformation and translation. Dissertation available from Univ Michigan Microfilms, Ann Arbor
	14. Hare M (1993) The emergence of an urban U. S. Chinese medicine. Med Anthropol Quart 7:30-49
	15. Kirk J, Miller ML (1986) Reliability and validity in qualitative research. Sage Publications, Thousand Oaks
	16. Marshall C, Rossman GB (1989) Designing qualitative research. Sage Publications, Thousand Oaks
	17. McCracken G (1988) The long interview. Qualitative research methods, Vol 13, Sage Publications, Newbury Park
	18. MacPherson H, Kaptchuk T (1997) Acupuncture in practice, case history insights from the west. Churchill Livingstone, Edinburgh
	19. Miles MB, Huberman AM (1994) Qualitative data analysis. Second edn. Sage Publications, Thousand Oaks
	20. Morse J, Field PA (1995) Qualitative research methods for health professionals. Second edn. Sage Publications, Thousand Oaks
	21. Schlusser G (1992) Coping strategies and individual meanings of illness. Soc Sci Med 34:427-432
	22. Yin R (1994) Case stud- research, design and methods. Second edn. Applied Social Research Methods Series, Vol. 5. Sage Publications, Thousand Oaks
Recommended Reading

	Brody H (1987) Stories of sickness. Yale Univ Press, New Haven
	Carmines EG, Zeller RA (1979) Reliability and validity assessment. Quantitative applications in the social sciences. Sage Publications, Thousand Oaks
	Gephart R (1988) Ethnostatistics: Qualitative foundations for quantitative research. Sage Qualitative Methods, Vol 12. Sage Publications, Thousand Oaks
	Lee ES, Forthofer R, Lorimor R (1989) Analyzing complex survey data. Quantitative Applications in the Social Sciences. Sage Publications, Thousand Oaks
	McDowell 1, Newell C (1996) Measuring health, a guide to rating scales and questionnaires. Oxford Univ Press, Oxford
	Ogles BM, Lambert MJ, Masters KS (1996) Assessing outcome in clinical practice. Allyn and Bacon, Boston
	Reissman C (1993) Narrative analysis. Qualitative research methods, Vol 30. Sage Publications, Newbury Park
	Schuman H, Presser S (1996) Questions and answers in attitude surveys. Sage Publications, Thousand Oaks
	Stewart AL, Ware IE (1992) Measuring functioning and well-being, the Medical Outcomes Study Approach. Duke Univ Press, Durham
	Streiner DL, Norman GR (1989) Health measurement scales: A practical guide to their development and use. Oxford Univ Press, Oxford
  CHAPTER 10

  Proposed Standards of Acupuncture Treatment 
 for Clinical Studies

G. Stux • S. Birch

10.1

Introduction

	The quality of clinical trials of acupuncture conducted since the early 1970s is often poor. General reviews and formal evaluations of the literature are uniform in this finding [22, 23, 26, 27, 30, 32, 34, 37-39, 43, 51, 53, 55, 59, 66, 67, 70-741. While the literature evaluating these clinical trials continues to grow, it has focused largely on the methodological quality of the study designs and the soundness of their results, but there has been little discussion of the adequacy of the acupuncture treatment itself. A few authors have suggested that the quality or adequacy of the acupuncture in these clinical trials maybe problematic [17, 32, 57, 63], and some have discussed guidelines to suggest what constitutes adequate treatment [4, 64]. There is generally a paucity of systematic analysis of the adequacy of the acupuncture tested in these clinical trials. One review team merely assessed whether the treatment was reported or not [34, 66, 67]. Another team attempted to develop criteria for such an evaluation but experienced difficulties with the method selected [39]. This essay will outline criteria for evaluating the adequacy of treatment in acupuncture studies, present evaluations of the adequacy of a number of clinical trials, and describe a systematic method for ensuring adequacy in future studies. Preliminary versions of some of these methods and data have been presented in previous research conferences and publications [4-6, 23, 64].
10.2

Acupuncture Treatment - What Is Involved?

	When acupuncture is administered, several decisions are made as the basis for selecting the optimal treatment:
	1. What are the most appropriate sites of treatment for a patient?
	2. What is the optimal number of treated sites?
	3. What is the optimal number of treatment sessions?
	4. What is the optimal frequency of treatment?
	5. What techniques of treatment should be applied at each treated site and what tools are best used to do this?
	6. Is acupuncture to be used alone or as a complement to standard therapy?
	Prior to asking these questions, two more questions are usually raised: who shall administer the acupuncture treatment and what are that person's training requirements?
	The treatment is usually selected based on answers to all these questions. However, many of the questions are not explicitly addressed or answered in the acupuncture literature and hence in practice. Most texts describe how one should apply the prescribed treatment once the diagnosis is selected, with certain pluses and minuses according to the patient. But this process is not always an explicit one and, as happens in many areas, the decisions and issues are constantly evolving. Take for example the treatment of drug addiction using acupuncture. Addiction is a complex health problem for which acupuncture has been applied over the last 25 years. The treatment was initially applied by needling the auricles with additional electrical stimulation of the needles [75]. Then, as it became more widely used, needles started being used alone, at set points that practitioners had noticed seemed to be most helpful 112). These treatments were added into existing treatment programs where group and individual counseling is the standard treatment 1131. Many using this approach stated that the counseling was an essential part of therapy and that the acupuncture should be used principally as an adjunctive treatment. It was also recommended that the acupuncture be applied daily if possible, at least for the detoxification stage of treatment, and then as needed. Clinical trials testing the auricular needling then started being conducted. However, a close examination of them reveals a certain heterogeneity in the approach. Some used three, some four, some five auricle points, and some used additional body acupoints [ 14, 48]. Most used the acupuncture adjunctively to the standard counseling therapy, but some used it alone without concurrent counseling [40). Frequency of treatment also varied. Reviewers examining the clinical trial literature of acupuncture in the treatment of addictions have expressed their frustration with the variability of approaches, noting the need for a more standardized approach [511.
	The variation in this area of acupuncture practice and trial literature is not unique. In general, we can say that acupuncture is not a homogenous method, unvarying in its applications in the different countries and cultures where it is used [9]. There are many different models of acupuncture practice and many different methods and techniques that may be used [7]. Thus, the answers to the above series of questions are usually tailored to the training and background of the acupuncturist asking them. For example, the traditional Chinese medicine (TCM) acupuncturist is trained to identify the "zheng," or pattern giving rise to the patient's complaint, and to treat this while also applying treatment to relieve the symptoms. In the TCM model, there are hundreds of possible zheng [76). The practitioner of the Japanese Keiraku Chiryo style is trained to identify one of only four patterns, or "sho", and apply treatment to correct this and relieve the symptoms [61). Some styles of acupuncture do not apply any particular assessment methods to determine a sho or zheng, but rather they apply treatment simply to relieve the symptoms 1191. As a consequence of this diversity, we must recognize the following if we are to proceed with an examination of the standards for acupuncture treatment in clinical studies of acupuncture:
	1. To test a particular style or method of practice, care must be taken to ensure that relevant methods are used. Thus, in answer to the series of questions above, it is important that each answer is congruent with that style or method of practice. If testing the TCM style of acupuncture, the characteristic "de qi" sensation should be obtained at each site of insertion as is prescribed by the literature [ 16] and, similarly, the zheng should be determined to be able to administer optimal treatment [11].
	2. Additionally, the conclusions of the study should discuss that style of acupuncture rather than acupuncture itself, as such generalizing may be misleading. For example, it would be misleading to discuss how acupuncture can treat addictions, since the treatment is principally of the auricles. It would be more precise to discuss the effects of auricular acupuncture.
	3. If one wants to test acupuncture itself and be able to start generalizing across the entire field, it is necessary to take the diversity of practice approaches into account. This requires a systematic method of examining the literature to find appropriate answers to the above series of questions. These questions and issues related to the diversity of practice approaches have not been addressed in most clinical trials, creating many problems in their interpretation.
10.3

A Systematic Analysis of the Adequacy of Treatment in Acupuncture Studies

	In an effort to understand the scope of the problem of adequacy of treatment in acupuncture studies, Birch conducted a review of the literature describing acupuncture treatment of chronic headache and low back or neck pain. Twenty-six Japanese, Chinese, and English texts were examined. This review found that a conservative minimum treatment for each condition involves ten treatment loci for a course of ten treatment sessions [4, 6]. (See below for details and examples.) Based on this review, 34 controlled clinical trials were examined to see if treatments approximated what was found in the literature review. Table 1 shows the results from applying these criteria to those 34 studies [6].
	Applying these basic criteria in the three chronic pain conditions, none of the 34 studies clearly administered adequate treatment. Some may have, but because of inadequate reporting of the treatment methods, it is not possible to determine this one way or the other [5]. When these minimum adequate criteria were relaxed, it was found that half the studies administered approximately adequate treatment (Table 1).
	Berman and colleagues conducted a formal review of 47 pain studies incorporating the above criteria for adequate and approximately adequate minimum treatment [23]. Using logistic regression analyses to examine the adequacy of treatment as a variable in outcome, they found that both the adequate and approximately adequate minimum treatments were significantly associated with a positive outcome when controlling for study quality [23]. This finding suggests that conservative minimum treatments derived from the literature reviews are valid.
	 SPECIAL_IMAGE-page0222_0000.svg-REPLACE_ME 
	A further examination of the clinical acupuncture trial literature found other related problems. Some reviewers found that the actual treatments are not described at all in some studies and that there is no source referencing of the applied treatments, thereby hindering determination of what treatments were actually applied [5, 32, 34, 66, 67]. In an analysis of 86 controlled studies, Kersken found that no description of therapy was given in 18 studies (21 %) and that no description of the number of treatment sessions or other important parameters were given in 19 (22%), [32]. Kersken found additionally that, while adequate descriptions were made of treatment principles in 15 of the 86 studies, 34 (40 %) did not [32]. It is hard to imagine a study of an analgesic drug where the actual drug and doses used are not described nor references given so that one can check elsewhere what was done; but the equivalent problem can be found in acupuncture studies 117, 18, 20].
	In his analysis of the acupuncture quality in 86 studies, Kersken found that only 33% describe obtaining a de qi response [32]. Pomeranz also noted that in many studies recommending the specific needle technique, elicitation of the de qi response (obtaining the qi) was not applied and that thus many studies did not adequately apply treatment [56]. While de qi is a very common method of needling and characteristic of some but not all forms of acupuncture [7], it is important that the study utilizes this technique when testing those models in which it is normally indicated.
	Some have also argued that the optimal use of acupuncture includes traditional diagnostic methods to individualize treatment appropriately for patients in clinical studies 117, 44]. While this is not necessarily a valid claim, given the diversity of practice approaches [6, 8], it is important to individualize treatments when testing models that usually employ these assessments. However, these methods require prior testing to establish their reliability [5, 69]. To date, very few studies of traditional diagnostic assessment methods have been conducted [69]. While evidence of the reliability of those assessments is slowly growing [8], it is still essential to incorporate reliability studies into future prospective trials that wish to use them.
	The training of the person administering the treatments can be an additional issue. In their three reviews, Ter Riet et al. addressed whether the training was mentioned in the 86 studies they reviewed [34, 66, 67], finding that "good quality of the acupuncturist" was mentioned in only 30 studies. Hammerschlag and Morris examined 23 studies to find that the acupuncturist's qualifications were mentioned in only one [27], a much smaller percentage than when all studies were pooled by Ter Riet and colleagues. However, mentioning the skill of the acupuncturist or simply stating his qualifications are clearly not enough, since training in acupuncture is not the same as real qualification to administer the treatment in a clinical study. For example, how much experience do they have?
	Obviously, more needs to be specified. Here we find a very contentious issue, as training requirements for acupuncturists vary considerably around the world [3]. There are places where physicians may practice with no training and others where practice is unregulated and anyone can practice. However, many countries and states within those countries have come up with some minimum training standards, but these vary tremendously from place to place. One of the principle variables has to do with whether the acupuncturist is also a physician. Typically, physicians study acupuncture in shorter programs than nonphysicians. Training programs for physicians can run from 1 or more weekends to several hundred hours; a review in Australia found programs that ranged from 50 to 390 hours [3). The recommended length of training programs for physicians in Germany is proposed to be 350 hours, 50% theoretical and 50% practical. The World Federation of Acupuncture and Moxibustion Societies (WFAS) recommends a minimum of 200 hours' training for physicians wishing to practice acupuncture [28]. Training for nonphysicians is usually at least 400 hours and can be substantially more [9]. For example, in Australia, training programs run from 1562 to 3824 hours [3], with the number of acupuncture- and TCM-specific training hours ranging from 906 to 2936 hours [3]. In the U.S., accredited programs contain a minimum of 2175 hours, with the average program lasting 450 hours more than this 1211. It is difficult to ascertain a clear minimum standard of training for acupuncturists in studies of acupuncture, but at the least a minimum needs to be established in the context of the country of study. Ideally, an approved course of study should have been completed. We would feel uncomfortable with a physician not experienced in a particular medical procedure to administer that procedure in a clinical trial.
	While we cannot generalize for all trials from these reviews, it does appear that there is a significant problem in how acupuncture treatments are tested in clinical trials. Putting aside questions about what some proponents believe are the correct styles of treatment [2, 17, 44], in simple numerical terms (number of points treated and number of treatment sessions), it appears that many clinical trials did not apply sufficient treatment. This is akin to testing a drug in a controlled clinical trial at inadequate doses for an inadequate length of time. If the results of such a trial were positive for the drug, many might consider it to be very effective and capable of working at lower doses than expected. Were the results of the drug trial negative, few would argue that it had been properly tested. However, knowledge of this issue has not yet been adequately incorporated into reviews of the acupuncture clinical trial literature. In the absence of such analyses, many reviewers assumed that the treatments were adequate and, upon finding little robust data or other problems with study design, concluded that acupuncture does not appear to be very effective [34, 66, 67, 711. Were analyses of the adequacy of treatment incorporated into such reviews, it could be that many authors would need to change their conclusions.
	In the following, we outline methods for determining what might constitute minimum adequate treatment in a clinical trial of acupuncture. These methods and their results can be used both in reassessment of the published literature and by researchers planning prospective studies. Based on the minimum adequate treatment, we then describe what might be the optimal treatment, or that expected to produce optimal results for a patient or group of patients.
10.4

Proposed Method for Review of the Literature

	Birch pointed out previously that one of the principal reasons for finding treatment inadequate was that many research teams appear to have read little of the available acupuncture literature, as evidenced by the lack or inadequate citation of sources in published studies [5], some even citing no acupuncture literature at all [17]. The solution to this problem is obviously that more acupuncture literature needs to be read before researchers embark on clinical trials. But here there are still a number of issues that will need to be dealt with:
	1. There are often problems with the literature itself [5]
	2. There are problems stemming from the nature of the question to be addressed and the related issue of generalizability of results [5, 111
	3. There is a problem with variability in the literature [6, 12]. We propose a systematic and extensive literature review to address these issues in each relevant area.
	Table 2 illustrates how the literature review process is applied. It shows the findings from a review of 18 texts describing the treatment of low hack pain by acupuncture. The recommended treatments in each text are compiled to show the ranges and averages of recommended numbers of treatment points and sessions. The review included a variety of texts from different approaches, so that when averaging the recommended numbers of points and sessions, we can increase the generalizability of results. The points recommended by each text for low back pain and the various subcategories of low back pain are recorded. By examining the specific points, the total number of discrete sites to be treated could be extrapolated. If the text indicated the number of treatment sessions necessary, this is also recorded.
	According to these sources, low back pain is treated with 2-14 points, or 3-28 needles, at an average range of 5.1-7.8 points and 9.5-13.8 discrete sites per treatment. Further, at least ten treatments need to be given, which matches clinical experience [64[. It thus appears that at least ten discrete sites treated for at least ten sessions can be considered the minimum adequate treatment for chronic low back pain. Hence, treatment should involve these parameters in a clinical trial for chronic low back pain.
	Acupuncture texts rarely discuss the number of sessions and frequency of treatment. As shown in Table 2, only three of 18 texts discussed the recommended number of treatments, and frequency is recommended even less often. Since this is a common problem, it will be necessary to use additional methods to determine the appropriate number and frequency of treatments. Since the literature is not forthcoming on this, it would be useful to conduct practitioner surveys to ascertain actual practice habits and augment this with expert panel reviews.
	 SPECIAL_IMAGE-page0227_0000.svg-REPLACE_ME 
	It is possible to use the same overall process to examine the recommended treatments within a specific style or tradition, such as zhong yi or TCM. Table 3 summarizes the findings from a review of 16 different TCM acupuncture-related texts ] 11 ]. Quite a wide range of diagnostic patterns were found (3-19 patterns, median 3.5).
	Four TCM diagnostic patterns of chronic low back pain were commonly discussed. The recommended numbers of points and discrete sites of treatment are [11]:
	1. Cold damp: mean 6.6 points (range 3-12), mean 9.6-11.5 discrete sites (range 5-21)
	2. Kidney yang vacuity: mean 6.4 points (range 5-9), mean 10.3-10.4 discrete sites (range 8-14)
	3. Kidney yin vacuity: mean 6.3 points (range 5-8), mean 11.7-11.9 discrete sites (range 9-15)
	4. Blood stasis: mean 6.4 points (range 2-11), mean 11.2-11.8 discrete sites (range 3-20)
	Thus, in a study testing TCM acupuncture for low back pain, the considerable variation in the literature makes selecting the treatment somewhat complicated. However, these four TCM diagnostic categories could be used, with the conservative minimum treatment for each category given as ten sessions each with treatment of 10, 10, 12, and 1 1 discrete sites, respectively [ 11 ].
	The literature review methods described above can be used between or within traditions of practice to examine what might constitute an adequate treatment in any condition for which acupuncture is used. Table4 summarizes results of similar reviews on the acupuncture treatment of neck pain, headaches, and asthma.
	 SPECIAL_IMAGE-page0230_0000.svg-REPLACE_ME 
	One review of acupuncture treatment of osteoarthritis showed that this literature review method can encounter difficulties. These difficulties arise in part because of considerable inconsistencies in the acupuncture literature, in part from difficulties with terms, and in part because this condition has many manifestations, some of which are described separately. In a review of 34 texts from the world literature, only 15 had any actual description of the treatment of arthritis, including osteoarthritis. In these texts, a range of 3-16 sites of treatment were recommended, depending upon location of the arthritis and text reviewed.
	These difficulties with the osteoarthritis literature suggest that it may be possible to use the number of treatment sessions only as the cutoff point for determining adequacy of treatment in each trial examined, since the selection of treatment points is quite varied. However, were there an effort to incorporate an analysis of the extent of treatment into each session, then it may also be advisable to use the above recommendations as tentative guidelines for discussion by a group of carefully selected experts. It would be better if this group had broad representation of the major traditions of practice so that its considerations could be more generalizable.
	It should be noted that the methods cited in Tables 2-4 yield a range of number of acupoints and discrete sites to be treated for each condition. We assumed that the lower end of that range should constitute the minimum adequate treatment for the given condition. In their review of pain studies, Berman and colleagues found that the cutoff point for minimum adequate treatment was a significant predictor of treatment outcome [23[. It thus appears that this guideline is useful in analyses of published studies. However, when designing prospective studies, it is advisable to define adequate treatment in more positive terms such as "optimal," so there can be no doubt that the treatment tested was a fair test of acupuncture.
	Defining this optimal treatment can be somewhat difficult. It is possible to use the higher ranges of average numbers of acupoints and discrete sites of treatment as optimal. For example, the data in Tables 3 and 4 would therefore suggest using 14, 14, 15, and 17 sites for the treatment of low back pain, neck pain, headache, and asthma, respectively. It may also be necessary to process these data with surveys of practitioners and expert panels to achieve a greater level of agreement on the optimal treatment in a particular condition.
	 SPECIAL_IMAGE-page0233_0000.svg-REPLACE_ME 
10.5

Proposals for Systematizing the Selection of Acupuncture in Clinical Trials

	Since many clinical trials of acupuncture use so-called sham or irrelevant acupuncture as the control treatment, the method used for selecting the appropriate and adequate acupuncture treatment could also be used to select the control treatment [4, 5]. A systematic method of ensuring that an appropriate control treatment is selected can be just as important for selecting the test treatment. The following proposal provides a method for selecting both types of treatment.
	In addition to selecting the test and control treatments, it may be possible to tackle the problem of generalizability of results. To date, this problem has not been welladdressed. Is it possible to generalize the results from one study of acupuncture to other studies or acupuncture as a whole? What must we to do to ensure or enhance the generalizability of results? The broad range of therapeutic techniques and approaches in the field [7, 9, 22] can be problematic in this sense. However, it may be possible to develop a method allowing generalization of results across methods or at least increased generalizability without repeating logical errors.
	A reproducible method for selecting both test and control treatments is needed. The Birch relevant and irrelevant treatment selection (BRITS) method is offered as a solution to this problem. Essentially, it seeks to establish treatment validity and improve generalizability of results through extensive literature reviews. Developed in early 1993 and named by one of the authors, this method was first presented at the Second Symposium of the Society for Acupuncture Research in September, 1994 [4] and has since been adopted in major clinical acupuncture trials in the U. S. These include trials for chronic neck pain at Harvard Medical School [10] and cocaine dependence at Yale University School of Medicine [49], and a large multicenter trial for cocaine dependence through Columbia University including the substance abuse treatment centers at the Universities of Yale, Minnesota, Miami, Washington, and California at Los Angeles and San Francisco [50]. Other, smaller studies in the U. S. have also utilized this method.
10.6

The BRITS Method

10.6.1

Purposes

	In brief, the BRITS method aims to develop:
	1. An easily applied standardizable approach to selecting and validating relevant acupoints for the test treatment in needle controlled acupuncture studies, thereby helping ensure appropriateness and adequacy of the test treatment.
	2. An easily applied standardizable approach to selecting and validating irrelevant acupoints for the control treatment.
	3. A pool of standardized irrelevant acupoints for specific conditions that can be used in future needle-controlled studies.
	4. A method that allows for a broad generalization of the results of controlled acupuncture studies using that method.
	5. Aid in formulating assessment criteria used to evaluate the quality and quantity of the test and control acupuncture treatments in published clinical trials.
10.6.2

Selecting and Validating Test (Relevant) Treatment Points

	The BRITS methodology for determining relevant treatment points uses the following guidelines:
	1. Review treatment texts or papers directly related to the method or tradition of practice being tested. Confirm that all acupoints to be treated are recommended for the condition in a minimum number of sources, e.g., at least six.
	2. Review other treatment texts to confirm that the treatment points are generally indicated in these other texts for the condition at hand. This step enhances the potential generalizability of the results and is optional, but preferred.
	3. Test the treatment in a pilot study before going to a full-scale study. Data from the pilot study can help fine-tune the design and size of the larger follow-up studies. This step is preferable but not always necessary.
10.6.3

Selecting and Validating Control (Irrelevant) Treatment Points

	To determine control treatment points, the BRITS method uses the following steps:
	1. Review the same treatment texts and papers used to validate the test acupoints and pick out the same number of inappropriate points as test points.
	2. The selection criteria for these points should be:
	A. They are hardly or not at all mentioned as being good for the condition or related conditions being treated in the study.
	B. They are in similar regions of the body. The credibility of the control treatment will likely decrease if the treatment is perceived as being ridiculous or unrelated to the pain. Needling in the proximity of the pain will tend to appear more credible.
	C. Always test the control treatment in a pilot study before going to a full-scale study. This will allow estimates of relative effectiveness of the control treatment to be made. These can then be used to determine the appropriateness of the control and make sample size calculations for larger scale studies 14, 61. If the control treatment appears almost as effective as the test treatment, it may he an inappropriate control treatment. Additional steps may be required to investigate this further 149, 501.
	This method provides a greater guarantee of validity of selected "active" and "control" treatment sites than previous methods and, by including a broad range of literature from diverse sources, it increases the generalizability of results. The more agreement there is about a particular concept or method across varied traditions of practice, the greater the generalizability of that concept or method to the whole field.
	If the literature review yields unclear results, as was found with the osteoarthritis review discussed above, it should be augmented by practitioner surveys and a panel of experts. These experts could use the review findings as a starting point for their considerations. Once a majority or consensus opinion develops, this can be used to outline treatment protocols in a particular study.
	The following example illustrates how the BRITS method can be used. In their study of acupuncture in the treatment of chronic neck pain, Birch and Jamison reviewed 24 classical Chinese, modern Chinese (including English language texts), and modern Japanese texts to determine the most commonly referenced local points for the treatment of neck pain and validate the selection of nonlocal points [6, 10]. The same texts were also reviewed to select points that were never cited in the treatment of neck pain; these were used as the control or irrelevant treatment points. Reviewing these texts allowed for the derivation of treatment protocols that were supportable by a significant body of modern and historical literature. In addition, the protocols had broad generalizability because of the selection of treatment points from a variety of schools and traditions. The review also justified the selection of the specific treatment techniques used.
	Coupled with the broader literature reviews discussed above, this method allows one not only to ascertain the minimum adequate treatment (numbers of discrete sites and number of treatment sessions) for the condition studied, but also the choice of specific acupoints themselves. It is also possible to use this method for focusing on the specific techniques to be tested.
	Extending this concept of minimum adequate treatment, we can derive an optimal treatment, one we think will produce optimal results. The BRITS method allows for precise selection of treatment points and associated methods. However, as we saw above, the literature usually specifies little about numbers of treatment sessions needed. In 1995, Stux addressed this issue. For example, he recommended that at least 16 treatments be administered for headache and migraine [64]. Generally, it is poor research practice for a study to discover after the fact that an inadequate treatment or dose of treatment had been administered. To compensate for this, we feel justified in recommending to guarantee optimal treatment. Our recommendations for optimal treatments in clinical trials of acupuncture are as follows:
	1. Since the reviews of the treatment of head, low back, and neck pain found a minimum of 10-11 and a maximum of 14-17 treatment sites (Tables2, 4), we feel it is better to use an average of 15 sites per treatment. Variations on this should be based on an extensive literature review and, if necessary, practitioner surveys complemented by expert panel reviews. However, if the goal of a particular study is to look only at palliative care, the reviews for chronic pain suggest that six sites of stimulation in each of six treatment sessions appears to be a good cutoff point for minimum adequate treatment [23]. In the treatment of asthma, our review suggests that the optimal treatment should involve 17 sites (Table 4).
	2. There has been little discussion of numbers of treatment sessions needed. However, our reviews suggest that for the treatment of chronic pain, a minimum of ten sessions is needed (Tables 2, 4). Thus, for optimal treatment, we feel it better to err on the side of too much, so at least 15 treatment sessions should be administered (except as mentioned for palliative care). In treating asthma, optimal treatment probably should involve more than 15 and possibly as many as 20 treatment sessions (Table 4).
	3. Frequency of treatment is discussed even less often than number of treatment sessions. However, we feel again that it is better to err on the side of the optimal treatment and that treatment should be at least twice per week (more, for example, with addiction), and cut back to once a week or less, based on some algorithm.
	4. Treatment techniques should match the practice model being tested. If a TCM acupuncture model is being used, de qi should be elicited at all points. If electrostimulation treatment is being tested, it is important to specify the machine, intensity and frequency of stimulation, wave form used, etc. Each technique should be justified through an appropriate literature review. The type and gauge of needles and depths of insertion should all be recorded, as well.
	5. Inserted needles are usually retained for some minimum length of time. This length is not always specified. However, we feel it most appropriate to retain them for at least 15-20 minutes and longer, as necessary. Since our approach is to recommend in favor of optimal treatment, we feel that if the study is to retain needles for less than 15 minutes, it should justify this through an appropriate literature review.
	6. An important issue barely raised in the literature is the adequacy of training of the person administering the acupuncture. It is not enough merely to state that the person had some training. Perhaps the safest standard is that the person administering the treatments should have completed an approved course. It is clearly not appropriate for a so-called surgeon from China to administer the acupuncture, nor is the completion of a single weekend of training sufficient. We discussed above the variation in training programs. Further work is necessary to establish an international standard for the training of acupuncturists in clinical trials but, at least for now, ensuring that the acupuncturist satisfies the standards in the country of practice should be sufficient. Additionally, it is probably advisable that the acupuncturist have a minimum number of years of experience.
	7. Finally, it is evident that the methodology of most acupuncture studies has been poor. It is therefore recommended as a matter of course that any proposed study bring in the services of at least three different experts: an acupuncture expert (separate from the person administering the treatment), an expert in methodology, and a statistical expert. With appropriate advice, it is hoped that the methodology in future studies of acupuncture will improve.
10.7

Conclusions

	It is apparent from the above discussions that there is considerable variety in how acupuncture textbooks describe the treatment for a particular condition. This variety exists even among texts purportedly describing the same tradition of practice. It is also apparent that the adequacy of treatment in clinical trials of acupuncture has been poor, raising yet more questions about how to interpret such trials. Further, with inadequate reporting of treatments and their origins, it is likely that idiosyncratic treatments have been tested, raising still more questions about the generalizability of results. There is clearly a need for a method that helps guarantee adequacy of treatment in future studies and helps resolve contradictions in the acupuncture literature itself.
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	78. Wu Y, Fischer W (1997) Practical therapeutics of traditional chinese medicine. Paradigm Publications, Brookline
	79. Ying ZZ, De JH (1997) Clinical manual of Chinese herbal medicine and acupuncture. Churchill Livingstone, New York
	80. Zheng EQ (ed) (1990) Chinese acupuncture and moxibustion. Publishing House of Shanghai College of TCM, Shanghai
  (:tt.st't t t I I

  Assessing Clinical Efficacy of Acupuncture: 
 Considerations for Designing Future Acupuncture Trials

L. Lao • J. Ezzo • B. M. Berman • R. Hammerschlag

11.1

Introduction

	The recent interest in acupuncture has led to an unprecedented amount of research funding in this area. This chapter presents a systematic, stepwise approach to research. It proposes investigating the efficacy of acupuncture by adapting the U. S. Food and Drug Administration (FDA) approach to clinical trials (Table 1). Two examples, one for chronic osteoarthritic (OA) pain [1, 2] and one for acute postextraction dental pain [3-5] are used to demonstrate how this method can be applied to acupuncture research. The final section discusses ways to integrate Western medicine more closely with traditional Chinese medicine (TCM) in research.
11.2

Phase I

	According to the FDA description, phase I trials are small, typically do not have a control group, and are designed to establish basic parameters of dose and safety (Table 1). The phase I OA trial [2], for example, consisted of 12 patients with no control group. Although acupuncture has already been recognized as generally safe, establishing an adequate dose (i.e., a specific acupuncture protocol) in a phase I trial is a major challenge. This has seldom been done in past trials. Consequently, a number of randomized controlled trials (RCTs) of acupuncture have administered acupuncture treatments not based on preliminary data. The following key items should be considered in a phase I acupuncture trial: dose, primary and secondary outcomes, follow-up time, and safety.
	 SPECIAL_IMAGE-page0242_0000.svg-REPLACE_ME 
11.2.1

Establishing an Adequate Dose

	Establishing an adequate treatment/dose of acupuncture is one of the fundamental first steps of a trial. In the past, many acupuncture treatments used in trials have been shown to be inadequate according to minimal criteria [6 and see Chapt. 10]. The fundamental decisions a researcher must make when establishing an adequate acupuncture treatment pertain to:
	1. Type of acupuncture treatment (e.g., TCM, Japanese, five-element)
	2. Formulaic vs. individualized treatments
	3. Qualifications/experience of the acupuncturist
	4. Point selection
	5. Depth and techniques of needle manipulation, i.e., manual (reinforced or reducing technique) or electrical stimulation (frequency and intensity)
	6. Whether de qi will be pursued
	7. Duration of each treatment
	8. Number of treatments per week and spacing between treatments
	9. Total number of treatments.
11.2.2

Formulaic vs. Individualized Acupuncture

	The ongoing debate about whether to use formulaic or individualized acupuncture revolves around two points of view. Those who argue for individualized treatment suggest that this approach reflects clinical reality whereas formulaic approaches do not. Those who argue for formulaic approaches suggest that individualized approaches may compromise methodological rigor and that a standardized treatment is less likely to create unintended confounders or noise in the study. There is no golden key that fits all the locks. Both methods are useful if the design is appropriate. Part of the decision depends on the condition being treated. Homogeneous populations are more conducive to formulaic acupuncture than are heterogeneous populations. For example, formulaic acupuncture was used in the postextraction dental pain study [3-5]. All the patients shared the same Western medicinal diagnosis (postoperative acute pain) and the same traditional Chinese medicinal diagnosis (excess heat condition with qi and blood stagnation), making this group an exceptionally homogeneous patient population. Heterogeneous populations in whom multiple signs and symptoms are treated, e.g., quality of life, pain, function, and mental status, may require individualized treatments.
	Deciding on formulaic vs. individualized acupuncture can also be an integrated rather than either/or approach. For example, both can be considered in a stepwise approach, progressing from the more rigorously controlled (formulaic) to the more practical (individualized). If results are positive using a formulaic approach, then research can progress into individualized treatments based on TCM diagnoses. Another integrated approach is to select comprehensive formula points which cover multiple TCM diagnoses. For example, the formulaic treatment used in the osteoarthritis study [ 1 ] covered most of the TCM points that would have been used, had individual syndromes been treated. Yet another option is to include at least one point from every TCM diagnosis. An additional compromise between formulaic and individualized protocols is to stratify patients by TCM subgroup diagnosis and treat patients at subgroup-specific acupoints (see discussion of double screen design later in this chapter).
11.2.3

Training/Experience of the Acupuncturist

	How skilled and experienced the acupuncturist should be in clinical trials is another common question. Proficiency requirements of the acupuncturist may differ, based on whether formulaic or individualized treatments are used. Obviously, when individualized treatments are given, the acupuncturist must be very experienced in both diagnosing and treating the condition under investigation in order to make treatment decisions based on TCM diagnoses. However, when formulaic treatments are given, it may suffice for the acupuncturist to demonstrate proficiency and replicability of the needling technique being used.
11.2.4

Selection of Points

	Birch has observed [7] that there is no consensus among acupuncture textbooks on the points to use for a given condition. The absence of standardized treatments makes it important to base the selected points both on the literature and personal clinical observations of effectiveness.
11.2.5

Total Number of Treatments

	The sufficient total number of treatments to administer in a trial, especially for chronic conditions, is largely unknown and seldom specified in the literature. Phase I presents a low-cost opportunity to establish both total number of treatments and the frequency of treatments for the investigated condition. In establishing these parameters, outcomes need to be measured frequently to determine when improvement begins and whether additional improvements occur with more treatments. For example, in the osteoarthritis study, both clinical experience and prior RCTs in the literature suggested that treatments twice weekly for three weeks were probably not adequate [8-10]. Phase I results showed substantial improvements at 4 weeks and continued improvements at 8 weeks. Therefore, treatment twice weekly for 8 weeks was selected as the treatment modality for phase II.
11.2.6

Selecting Outcomes

	Phase I provides an opportunity to select appropriate outcomes to be tested. The outcomes should be measurable according to validated instruments. A validated instrument means that it has been demonstrated through prior research that it is measuring what it says it is measuring. Examples of well-validated general health assessment tools include the Sickness Impact Profile (SIP) [ 1 I ] and the SF-36 1121. Because these measurement tools have been validated using the whole instrument, it is a good idea when using these instruments to use them intact; using pieces of an instrument can jeopardize the validity of a trial. Instruments can be generic (measuring overall health status) or disease-specific (measuring clinically important changes pertinent to that specific disease) [13]. Frequently, studies include both. It is helpful to look at the recent literature pertaining to the disease under investigation in order to decide which instruments to use. Excellent, user-friendly guides on measurement selection exist [14].
	Another important decision to be made is which will be the primary and which the secondary outcomes. Primary outcomes, designated by investigators as the most important outcomes, should be limited to one or two, clearly defined, and used for calculating sample size in subsequent trial phases. Secondary outcomes can represent other symptoms of interest, quality of life, sleep patterns, appetite, bowel movements, and mental status. However, it is important to remember that because sample size is not based on secondary outcomes, significant changes between groups might not be observed in all of these secondary outcomes. For example, in the dental pain study [5], the primary outcome was pain-free time after surgery, and sample size calculation was based on that. A secondary outcome was pain relief after the first acupuncture treatment. Results showed a significant difference between groups in the primary but not the secondary outcome. One possibility for this finding is that, in reality, there is no significant difference in pain relief in real vs. placebo acupuncture once the pain has reached moderate intensity. However, another possibility is that the sample size may have been too small to detect a difference between groups in the secondary outcome. Similar situations have occurred in other acupuncture trials 115).
1 1.2.7

Choosing a Follow-up Time

	Selecting the appropriate follow-up time depends on the condition being tested and can be investigated in the early phases of a trial because, especially in chronic conditions, this may influence the final treatment protocol to be used in subsequent phases. For acute conditions such as dental pain [3-5], a week may be adequate to determine whether the treatment is effective. By contrast, for chronic conditions such as OA, a follow-up of 3, 6, or 12 months may be more appropriate [ 1, 2]. Long-term follow-up is important to determine long-term efficacy with acupuncture. If efficacy is not sustained, investigators can examine ways to sustain it.
	Follow-up data can provide useful information for designing future trial phases. For example, long-term follow-up data from two previous OA studies guided the formulation of the acupuncture protocol in the large, randomized OA trial. Firstly, longterm follow-up data by Christensen and colleagues [9] in a group of OA patients showed that improvements could be sustained for a year using monthly acupuncture after treatments twice a week had stopped. However, it was not evident from this study whether improvement would be sustained without booster treatments. Then, long-term follow-up data from Berman and colleagues [ 1 ] showed that, without booster treatments, pain scores returned to pretreatment baselines by 24 weeks. As a result of these follow-up data, the decision was made in a large OA trial to give monthly booster acupuncture treatments after patients had completed the 8-week treatment regimen.
11.2.8

Measuring Safety

	Unlike phase I trials for a new drug, which must closely examine safety, acupuncture is already considered safe. However, it is important as part of any clinical assessment to document adverse events. Confusion arises when a paper mentions that no adverse effects were observed. Frequently, it is not clear whether adverse effects did not occur or simply were not measured. Therefore, it is advisable to have an explicit and systematic methodology such as a symptoms checklist for documenting side effects. Phase I provides the opportunity to refine the checklist based on the condition being investigated.
11.2.9

Comment

	The major advantage of a phase I trial is that it enables investigators to generate preliminary information on dose and safety in a cost-effective way. If no benefit is observed during phase I, it may be because the selected acupuncture protocol (dose) is not appropriate and/or because the condition under investigation is not responsive to acupuncture. In such a circumstance, the researcher might alter the acupuncture protocol or inclusion/exclusion criteria and conduct another phase I trial. If patients do not respond, then the researcher knows early on that the research question may not be worth pursuing in a larger, more costly, randomized controlled trial.
	However, if benefit is observed in phase I, it cannot be assumed to be due to the acupuncture protocol. This is because phase I trials have no control group and are not efficacy trials. There are three explanations for why patients may experience benefit during an intervention: (1) treatment effects, (2) nonspecific effects, and (3) disease remissions [ 16]. To be able to attribute improvements to treatment effects, the investigator must first rule out disease remissions and nonspecific effects. "Nonspecific effects" is frequently used to describe all of the nontreatment effects which result from the milieu in which the treatment occurs, including the physical environment, the caring staff, and beliefs and expectations of the patients. Confusion arises in acupuncture trials because the term "nonspecific effects" is often used to describe physiological effects due to needling stimulation, such as diffuse noxious inhibitory control (DNIC). For clarity, this term will be used to describe nontreatment-related effects, and "nonspecific physiological effects of needling" will be used to describe the effects of acupuncture that result from needle stimulation but are not acupuncture point-specific. Ruling out improvements due to nonspecific effects and spontaneous remissions requires the use of a control group, which is commonly introduced in phase II.
11.3

Phase II

	Phase II trials build on the information gained in phase I. Phase 11 trials generally have a control group and generate additional information on dosing and safety as well as preliminary information on efficacy (Table 1). Comparison groups can concern different doses of the same treatment, different treatment, or placebo groups. Randomization is frequently done in phase II, although the numbers are generally small.
11.3.1

Selecting an Appropriate Control Group

	Unlike pharmaceutical research, in which a placebo is easy to design and double blinding is easily achieved, it is difficult to design an appropriate control group for acupuncture, because acupuncture is an invasive, physical modality. No single control group can answer all the research questions. Therefore, many types of control groups, each with its own advantages and disadvantages, have been used, depending on the specific question being asked (Table 2) [171. In choosing an appropriate control group, it is important to consider what current treatments are available for the condition being investigated. If a condition already has an effective standard medical treatment, then it makes no ethical or financial sense to examine sham vs. real acupuncture. It is more logical to examine acupuncture effectiveness compared to standard care. In addition to overall effectiveness, it can also be noted whether acupuncture has a quicker onset, lasts longer, or has a milder side effect profile than standard care. It is also logical to examine whether additional benefit to standard care can be derived by adding acupuncture treatments.
1 1.3.2

Waiting Lists

	Waiting lists can track the natural history of a disease and assess for spontaneous remissions. Therefore, the value of a waiting list over not using a control group is that waiting lists provide a way to estimate remissions due to disease variation rather than treatment effectiveness. For example, in the OA trial [1], a waiting list control group was used. Both patient groups were instructed to continue using whatever medications they were already using. Acupuncture was administered immediately to one group and delayed in the other group. There were several advantages to the choice of this control group. It controlled for spontaneous remissions, provided clinically useful information on acupuncture as an adjunct to treatments already being used and offered an ethical design for the control group to receive the experimental acupuncture treatment. Obviously, the limitation to this group was that it could not control for placebo effects.
	The importance of controlling for disease remissions using a waiting list group was underscored in an acupuncture trial in which 30% in the waiting list group experienced remissions in pain [18].
	 SPECIAL_IMAGE-page0248_0000.svg-REPLACE_ME 
11.3.3

Nonacupuncture Inert Controls

	A placebo is a physiologically inert intervention. Sham transcutaneous electrical nerve stimulation (TENS) has been used in acupuncture trials to estimate placebo effects because it provides a control intervention that is undoubtedly physiologically inert and has been demonstrated to be a credible treatment [191. Unlike patients in the waiting list control, patients in the sham TENS group receive amounts of practitioner time and attention similar to those for patients in the acupuncture group. Therefore, the sham TENS group controls for some nonspecific effects, such as those resulting from patient-practitioner relationship. However, the placebo effect of acupuncture cannot be measured, because sham TENS does not resemble acupuncture. Patients cannot be blinded in a sham TENS vs. acupuncture trial. In other words, patients know whether they received acupuncture or not.
	Sugar pills, another type of nonacupuncture inert control, have also been used [20]. However, sugar pills bear even less resemblance to acupuncture and cannot control for the nonspecific effects resulting from the patientpractitioner relationship, because the practitioner time and attention is not comparable in patients receiving acupuncture relative to those receiving sugar pills.
11.3.4

Placebo Acupuncture

	Placebo acupuncture is a true control for the acupuncture treatment because it is not only physiologically inert but also resembles real acupuncture. In placebo acupuncture, the blunt end of the needle [21], acupuncture needles, or objects resembling needles such as toothpicks [22], needling guiding tubes [3-5], or specifically designed noninsertion needling devices 123, 24] create the appearance of insertion but are not actually inserted.
	In order to enhance the success of patient blinding in placebo acupuncture, some investigators [3-5] exclude patients who have previously received real acupuncture. Patient blinding might also be improved by creating the expectation that acupuncture is painless, such as by showing placebo patients that the diameter (<_ 0.2 mm) of the commonly used acupuncture needle is much thinner than hollow hypodermic needles. Placebo acupuncture may be especially useful in short-term, acute intervention trials. A possible disadvantage is that in conditions requiring long-term treatment, maintaining patient blinding may be difficult. This is because curiosity of the patients to discover the type of treatment they have been receiving may lead to unblinding (e.g., patients may talk to each other, read about acupuncture, or go to another acupuncturist). A few investigators [3-5, 22, 32] have checked the blinding credibility after the placebo intervention by administering a questionnaire asking patients which treatment they believe they have received. This procedure is important in order to validate whether blinding has succeeded.
1 1.3.5

Sham Acupuncture

11.3.5.1

Sham Acupuncture for Measuring Nonspecific Effects of Needling

	Unlike placebo acupuncture that involves noninvasive procedures, sham acupuncture involves actual needling but at sites inappropriate to the condition being examined 18,11, 25-28]. Like placebo acupuncture, the advantage in sham acupuncture is its resemblance to real acupuncture so that patients can be blinded to treatment group assignment. However, since sham needling mimics both the nonspecific effects and the nonspecific physiological effects of needling, the difference between real and sham groups may be slight, especially in pain trials. Such nonspecific physiological effects of needling may include local alteration in circulation and immune function [29] and triggering of neural pathways such as those resulting in diffuse noxious inhibitory control (DNIC) of pain [30].
	In order to minimize the nonspecific physiological effects of needling, the sham procedure may use distal points, minimal needling depth, and minimal needle stimulation rather than local points, standard depth, and needle stimulation 1311. Avoiding de qi in the sham group is also important. Because of the magnitude of these nonspecific needling effects, careful consideration is needed to calculate an adequate sample size. As in placebo acupuncture, it is important to confirm patient blinding by providing a questionnaire asking patients which treatment they believe they have received [32).
	In addition to producing nonspecific needling effects, another disadvantage of sham acupuncture is that there is no general agreement as to how it should be designed [ 17]. For example, sham acupuncture may be applied by needling nonpoints adjacent to real points [26], nonpoints distal to real points [27], or real acupuncture points not specific for the condition to be treated [33]. Needling techniques in sham acupuncture can be applied at various depths, e.g., superficial or standard, with various types of stimulation, e.g., manual or electrostimulation, using various needle manipulation techniques, e.g., reinforcing, reducing, and changes in needling angles and directions, and retaining needles for various times, e.g., for similar or shorter duration than in treatment groups. These variations in the way sham acupuncture is applied make it difficult even to compare the results of two sham acupuncture trials investigating the same condition. For example, in an OA RCT, Takeda and Wessel [ 10] noticed that de qi was sometimes inadvertently elicited in the sham group and sometimes not elicited in the real acupuncture group. Although results showed no significant differences between groups, de qi was a predictor for significant improvement in both the Western Ontario and McMaster Universities Osteoarthritis Pain Index and the pressure threshold scores in both groups. Clearly, comparing the results of this sham acupuncture trial may not be comparable with the results of another trial which avoids de qi in the sham group.
11.3.5.2

Sham Acupuncture for Measuring Acupuncture Specificity

	Sham acupuncture is also the appropriate control for examining the validity of TCM claims for acupuncture point specificity. It can be used to test point specificity by comparing the physiological effects of needling a precisely located real acupoint to an adjacent nonpoint according to standard TCM textbooks. It can also test specificity by comparing the effects of needling a group of real points prescribed for a condition according to TCM theory to a group of inappropriate points. And it is useful for testing specific physiological effects of various needling techniques such as reinforced or reducing technique, or techniques that elicit de qi.
	When sham acupuncture is devised to investigate acupuncture specificity, different design issues need to be considered than when sham is devised to measure placebo effects. In the latter case, the goal is to minimize nonspecific physiological effects of needling and, therefore, several features of the sham procedure may differ from procedures with the real acupuncture group, including points selected, depth of insertion, and amount of stimulation applied to the needle. In contrast, when sham acupuncture is used in the former case as a control to examine acupuncture specificity, i.e., to test whether stimulation of a real point has greater physiological effects than a nonpoint, then all the features of the sham treatment should be identical to the real treatment except for the feature under investigation, i.e., point locations.
11.3.6

Combined Controls

	Combining various controls within the same study is a creative way to minimize the limitations of each type of control. It is apparent that a major challenge in acupuncture research is the ability successfully to blind patients to their treatment group assignment, because when the comparison group's treatment does not resemble acupuncture, blinding is impossible. One innovative approach is to combine various placebo interventions within the same study to make the treatments in the two groups appear comparable. For example, in comparing medication to acupuncture for migraine, Hesse et at. [211 gave real medication plus placebo acupuncture to one group and real acupuncture plus placebo medication to the other. This innovative approach enabled them to blind patients to treatment group assignment.
	Another challenge in acupuncture research is to develop placebos that resemble acupuncture while minimizing nonspecific needling effects. A rarely used, innovative approach is to combine both sham acupuncture (inserted needles) and placebo acupuncture (noninserted needles) in the same design. For example, in a recently funded dental study, the real treatment consisted of real acupuncture at points St.6 and 7, SJ.17, and LI.4. The placebo treatment consisted of placebo acupuncture (noninserted needles) administered to these same points. However, in order to improve blinding in the placebo group, a sham acupuncture (inserted needle) point was added to the leg 1 inch posterior to Liv.8, thereby ensuring that the placebo group experiences the sensation of needle insertion. Then, to make the two groups comparable in appearance, placebo acupuncture (noninserted needle) was added to the same leg point in the real acupuncture group. Combined controls such as these have two advantages: (1) blinding in both groups is enhanced because the two treatments are comparable in appearance, and (2) blinding in the real acupuncture group is further enhanced because the placebo leg point may make the real treatment appear less real.
11.3.7

Positive Controls

	The question asked in the type of research design that uses a positive (active) control group [341 is different from those asked with any of the above control groups: is acupuncture at least as effective as standard medical care such as medication, physiotherapy, or occlusal splint? This design is useful for conditions in which side effects of medications are problematic, since it allows for side by side comparisons of adverse outcomes [21, 351. Acupuncture can also be added to standard care to determine if it can increase the effectiveness of other treatment 1361 or even reduce the required dose 1371. Designs which assess acupuncture compared or added to standard care also provide an opportunity for cost effectiveness comparisons 1361. When planning a trial using positive controls, it is important to ensure adequate power, because otherwise nonsignificant results are difficult to interpret. It cannot be assumed that acupuncture has performed as well as standard care unless a type II error can be ruled out. A type II error occurs when there actually is a difference between the two treatments but the sample size is too small to detect it. Such results are not significant, but a larger sample size would have found a significant difference between the two treatments.
11.3.8

Selecting the Study Design: Parallel or Crossover

	A final consideration for phase II trials is which type of study design to select. Several acupuncture trials have used crossover designs, mostly for the sake of convenience, because crossover designs increase statistical power without increasing patient enrollment. Three assumptions must apply for crossover designs to be an appropriate experimental design: (1) the disease must be stable throughout the study, (2) there is no reason to believe that the treatments interact with each other, and (3) the effects of the proposed intervention cease soon after discontinuing the intervention[38].
	The latter point calls into question the appropriateness of crossover designs for acupuncture trials. Evidence of long-term effects of acupuncture have been observed in controlled clinical trials in which significant pain relief achieved after 6 weeks of treatment for migraine [26] or 3 months of treatment for dysmenorrhea [27] was maintained at I-year follow-up. Not surprisingly, carryover effects (treatment effects which persist long after treatment ceases) have been documented in crossover trials of acupuncture [39]. The presence of carryover effects in acupuncture studies suggests that crossover designs are an inappropriate design choice, except in trials with very long washout periods.
	Furthermore, in crossover studies comparing real versus sham acupuncture, it is questionable whether patients can maintain blindness to treatment groups once they have experienced both real and sham acupuncture treatments. For these reasons, parallel rather than crossover designs are preferred for acupuncture efficacy trials.
11.3.9

Summary and Example

	There are several advantages to conducting a phase II trial before plunging into a large, definitive phase III randomized controlled trial (RCT): it (1) allows for the hypothesis to be tested on a small, cost effective scale, (2) provides the data needed to do the power calculation for a larger trial, (3) assesses the feasibility of the research setting, including staffing availability, and (4) provides a forum where unforeseen problems can arise and be resolved so that a solid study protocol can be developed for the larger phase III randomized trial.
	For example, phase II of the dental pain trial [4] provided an excellent opportunity to refine the timing of activities within the trial. Prior to phase II, the treatment protocol had been based on a previous trial in the literature which administered acupuncture when patients experienced moderate pain [25]. However, during phase II, the investigators observed that acupuncture given pre-emptively was a more effective analgesic, so the protocol was modified accordingly.
	Another example was that phase II provided an opportunity to assess whether the timing of administering the blinding questionnaire was appropriate. Prior to phase II, it was determined that patients would be asked before they left the clinic which treatment they believed they had received. The investigators learned during phase II that, by that time, patients' guesses were based on their level of pain relief and were fairly accurate. However, when the question was asked immediately after the first treatment, prior to the experience of breakthrough pain, guesses were based on characteristics of the treatment, and the placebo acupuncture procedure was found to be credible.
11.4

Phase III

	Phase III trials are the definitive efficacy trials. They are large and often conducted at multiple locations. In the OA study, the phase III trial consists of a three-arm parallel design (n = 570) comparing real and sham acupuncture vs. an attention control group. The systematic reviews discussed in chapter 7 provide excellent commentaries on the methodological quality of acupuncture efficacy trials. This section proposes guidelines for strengthening acupuncture efficacy trials based on those commentaries. Obviously, many of these guidelines apply to both phase 11 and III trials.
11.4.1

Select Biologically Meaningful Inclusion/Exclusion Criteria

	One must be explicit about the biological rationale for the inclusion/exclusion criteria. For example, there are advantages and disadvantages to including heterogeneous study populations. An advantage of heterogeneous study populations is that the study results may be generalized to a broader group of people. Furthermore, as has been mentioned previously, it is unlikely that formulaic acupuncture can ever be devised for a very heterogeneous study population. The disadvantage is that heterogeneity may dilute treatment effects. In either case, the most important consideration is that the inclusion criteria make biological sense based on knowledge of the disease and of acupuncture.
11.4.2

Ensure Adequate Power

	The most universal observation made in systematic reviews of acupuncture trials is that, with few exceptions, the numbers of patients were notably small. This makes acupuncture trials difficult to interpret because they can be prone to type II errors. Type 11 errors occur when a study obtains a nonsignificant result although a significant difference between groups exists in reality 1401. Unfortunately, there is no way to tell whether nonsignificant results reflect reality or result from type 11 errors due to inadequate statistical power. To reduce the possibility of type II errors, it is important to base sample size estimates a priori on a statistical formula 1401, estimate expected differences from studies which used a control group comparable to the one intended for the planned study and, when possible, base sample size estimates on pilot data. It is best to recruit the skills of a biostatistician when addressing these statistical issues throughout the trial.
	Trials comparing real vs. sham acupuncture for the treatment of pain may be especially prone to type II errors because they have larger sample size requirements than trials comparing real acupuncture to inert placebos for the treatment of pain. This is because sham (invasive) needling induces nonspecific physiological effects that include partial pain modulation 1171. A systematic review of acupuncture [411 for chronic pain demonstrated that the proportions of patients responding to sham acupuncture were significantly higher than the proportions responding to inert placebos.
11.4.3

Minimize Selection Bias Through Adequate Randomization

	One of the most important potential biases can result from the way that patients are allocated to treatment groups. Known as selection bias, this is a systematic difference in the baseline characteristics of comparison groups [42]. Randomization offers the best way to balance known and unknown prognostic factors equally between groups. There are two distinctly important features in group allocation, both of which must be present in order to reduce the chances of selection bias: the first is that a true randomization procedure needs to be implemented (i.e., using a table of random numbers or a computer-generated randomizing scheme). The second, to be discussed in Section 11.4.4, is that the allocation procedure needs to be tamperproof.
	Small studies are prone to selection bias because they are unlikely to achieve balance on important prognostic factors. If imbalances in group allocation result in less severely impaired patients being allocated to the treatment group and more severely impaired patients to the control group, then selection bias can lead to an artificially high response rate in the treatment group. Small trials are often thought to be problematic only because insufficient power may lead to findings of no treatment effect. However, they can truly be problematic due to selection bias and actually overestimate treatment effects by as much as 30 % [43]. The importance of baseline comparability has led Linde et al. [44] to include a question in their quality checklist which asks whether groups were comparable at baseline. It is always a good idea to report baseline comparisons of the two groups in any of the study publications. The difficulty of how to interpret results of a trial when groups are not comparable in baseline characteristics was recently evidenced in an RCT for headache [22]. The results of this methodologically rigorous pilot study, which scored a perfect score on the ]adad scale, were deemed impossible to interpret [45] due to a baseline difference in the weekly headache index. More severe headache index scores clustered in the real acupuncture group, thus giving placebo acupuncture an unfair advantage.
	One way to assist the balance between groups is to stratify before randomizing. Generally, one or two factors known to be associated with the outcome of interest, such as CD4 counts in an AIDS study, are selected for the strata. Randomization is then done within each stratum.
11.4.4

Minimize Selection Bias Through Allocation Concealment

	Allocation concealment is a term used to describe the method by which foreknowledge of treatment assignment is prevented and the allocation procedure is kept tamperproof [42]. Each patient's eligibility for the trial should be determined before he is randomly given a group assignment. Once assignment has been made, both the treatment group assignment and the eligibility decision should be unalterable. Obviously, allocation concealment is more likely to succeed if the person responsible for allocation is not the same one responsible for recruiting subjects or assessing eligibility.
	Lack of adequate allocation concealment is more strongly associated with bias than how the randomization sequence is generated [42[. Lack of adequate allocation concealment can exaggerate treatment effects by as much as 41 '% [46[. Obviously, transparent allocation systems such as alternate assignment, open lists, allocation by date of birth, or pulling numbers from a hat are not sufficient. Systems which sufficiently conceal allocation can include calling a central office for the next allocation assignment or an in-house computer tile which yields the allocation only after the study identification number of the eligible person is entered.
1 1.4.5

Minimize Performance Bias by Blinding Patients and Practitioners

	Performance bias is a systematic difference in the way patients or practitioners behave as a result of knowing the treatment group assignment 1421. Performance bias in unblinded patients, for example, can result in patients' reporting more symptoms.
	Performance bias in unblinded practitioners can occur if the practitioner inadvertently treats the patients in treatment and control groups differently, such as being more caring or encouraging with those in the treatment group. Because practitioners can seldom be blinded in acupuncture trials, care must be taken to minimize practitioner performance bias. For example, the protocol might require that practitioners minimize verbal communication with the patient or use only standardized answers. It has also been suggested that videotaping treatment sessions could provide a way of detecting differences in practitioner behaviors so that they may be corrected while the trial is in progress [47).
	Clearly, the optimal way to prevent performance bias is to blind those providing and receiving care to treatment group assignment (called double blinding). If a trial is not double blind, effects can be overestimated 1431. Double blinding is seldom possible in acupuncture trials because blinding those who are receiving the treatment is not possible if the two treatments do not resemble each other, as in sham TENS vs. acupuncture. Therefore, investigators must anticipate how performance bias might be influencing results and find ways to minimize it.
1 1.4.6

Minimize Detection Bias by Blinding the Outcome Assessors

	Even when patients and practitioners cannot be blinded, the outcome assessor always can and should be blinded. Avoid detection bias by blinding outcome assessors. Detection bias is a systematic difference in the way outcomes are assessed due to lack of unblinded outcome assessors [42]. Put another way, unblinded outcome assessors may see what they want to see. This is particularly problematic in outcomes such as x-rays or global estimates of improvement that require a level of subjective judgment. It is less problematic in outcomes that require no subjective judgment, such as death. In acupuncture trials, unblinded outcome assessors who believe that acupuncture is beneficial may tend to find more global improvements or less disease progression in the real acupuncture group. It is important to note that some investigators use the term "double blinding" to mean that the outcome assessor is also blinded [48]. Therefore, it is important to ascertain exactly who is being blinded when "double blinding" is used.
1 1.4.7

Control for Cointerventions

	Cointerventions, those treatments other than the experimental treatment that the patient may use while enrolled in the trial, must be accounted for in order to ascertain if benefit can be attributed to the experimental treatment [49]. Cointerventions can include medications, massage, physiotherapy, meditation practice, or lifestyle changes such as diet and exercise.
	For example, one scenario might be that the control group does not experience benefit from the control treatment so that they turn to cointervention for relief. If cointerventions are not accounted for, then the two groups could appear to have equally effective treatments. This potential problem often leads trialists to ask patients to refrain from using cointerventions during the study period. When this is neither practical nor ethical, providing patients a way to document the use of cointerventions, such as recording in a daily diary, will provide a way to control for cointerventions in the statistical analysis.
11.4.8

Avoid Attrition Bias by Performing Intention-to-Treat Analysis

	Even if selection bias has been successfully prevented during the allocation stage of a trial, it can still occur during the follow-up trial if only completers are counted. Selection bias during the follow-up period due to dropouts and withdrawals is called attrition bias. Attrition bias, therefore, results from a systematic difference in withdrawals [42]. Intention-to-treat analysis, which treats dropouts as nonresponders, is the preferred statistical approach to preventing attrition bias. Examples of intention-to-treat analysis are a relatively recent occurrence in the acupuncture literature [ 1, 50].
	The rationale behind intention-to-treat analysis is to preserve the randomization scheme, thus preserving the balance in prognostic factors achieved during allocation to treatment group. Therefore, intention-to-treat analysis counts everyone who was randomized, including those who dropped out before ever receiving treatment, those who stopped coming for treatment, and those who were lost to follow-up. Although treating all dropouts and withdrawals as nonresponders may downplay the true effect of a treatment, it will not bias results.
11.4.9

Avoid Reporting Bias by Reporting on all Prespecified Outcomes

	Reporting bias, the systematic difference in how outcomes are reported, can occur during writeup [42]. Because some consider positive findings more interesting than nonsignificant findings, investigators might be inclined to report only those out comes which yield positive findings. The best way to prevent reporting bias is to specify in the planning stage of the study which outcomes will be measured and then to report on all of them, regardless of whether they yield positive or nonsignificant results.
11.4.10

Report p values, Relative Risk, and Confidence Intervals

	Randomized controlled trials typically report between group differences in p values. By convention, differences are considered significant if p< 0.05, which means a less than 5 % chance that treatment A is the same as treatment B. When p values are presented with the relative risks and confidence intervals are presented near the relative risk, then a great deal more information about the results is provided. P values alone cannot estimate the magnitude of the treatment effect or indicate the precision of that magnitude estimate. Relative risk (RR), on the other hand, is the ratio of the incidence of the outcome in the treated group to the incidence of the outcome in the control group. The 95 % confidence intervals are generally presented with the RR and used to estimate its precision. A 95 % confidence interval indicates a 95 'Yo chance that the difference between groups actually lies within that interval.
	As a case in point, consider the recent RCT assessing the efficacy of acupuncture for dental pain. 151 Using p values alone, it was reported that after the first acupuncture treatment, subjects treated with real acupuncture compared to placebo acupuncture reported a longer time to moderate pain (p = 0.008). Then, by using RRs and confidence intervals, the investigators presented additional information that could not be provided by p values alone. The magnitude of effect was depicted as an RR of 0.40, which indicated that those in the real acupuncture group were 60 'Yo less likely to experience moderate pain after third molar extraction than those in the placebo group. The precision of this estimate was depicted in the 95 'Yo confidence interval (0.19-0.84), which showed that, although the RR estimated that the real acupuncture group was 60 % less likely to experience moderate pain, the real estimate may be as high as 81 % or as low as 16 %. That the confidence interval did not exceed these limits indicates that the true effect is likely to be statistically significant.
11.4.11

Summary

	The three phases of clinical trials have been discussed in this chapter. By outlining the major goals in each phase of research, these FDA descriptions offer a model for acupuncture research that provides information valuable in every phase. This method enables acupuncture research to be simultaneously comprehensive and cost effective.
11.5

Toward an Integrated Research Model of Western and Traditional Chinese Medicine

	With acupuncture seeking acceptance in the West, it is understandable that the large majority of clinical efficacy trials have been framed by biomedical symptoms and designed according to the placebo-controlled model. Yet adapting the Western bio medical model to assess TCM has been likened to measuring Chinese distances with a Western ruler. The fundamental question becomes: what more can be learned from the tradition behind acupuncture and how can that knowledge be applied to optimize the potential health benefits? To answer this question means integrating Western biomedical and TCM diagnoses and treatments into the same conceptual framework. Once the paradigms of these two medical traditions are brought into the same clinical trial framework, the scope of questions that can be asked is broadened and the potential gain of information becomes apparent. It is a fair test of any medicine that clinical trials should be informed by and mirror clinical practice to the greatest extent possible. The remainder of this chapter proposes ways to integrate the two systems so that future research is better informed and reflects acupuncture as it is practiced.
11.5.1

Can Integrating Western and TCM Diagnoses in the Same Trial Improve Efficacy?

	As has been mentioned, a controversy exists in research concerning whether to use formulaic acupuncture in trials (which satisfies Western methodological rigor) or individualized treatments (which more closely approximates how acupuncture is practiced). Traditional Chinese medicine practitioners express concern that, by following only Western methodology, TCM loses its original meaning and its potentially greatest contribution to medicine - a unique way of diagnosing and individualizing treatments commonly referred to as TCM differentiation. According to the Western point of view, the same disease with the same symptoms presents the same diagnostic criteria; but according to the TCM point of view, it may constitute two or more TCM differentiations. For example, the Western treatment for chronic diarrhea may be universal, but the TCM treatment would be based upon the differentiation (Table 3).
	The double screen technique proposed in this section is designed to accommodate both Western and TCM diagnoses in the same clinical trial. It is applied when eligibility is being determined prior to randomization. During eligibility assessment, both Western and TCM diagnostic criteria apply. Firstly, the person is deemed eligible according to conventional medicine diagnosis, in this case chronic diarrhea. Next, he is deemed eligible according to TCM diagnosis made by a TCM practitioner. Because there may be several TCM differentiations, it is more appropriate to choose the most common ones (e.g., for chronic diarrhea, kidney yang deficiency, and spleen qi deficiency) for the practical reason that selecting a common TCM diagnosis will increase the likelihood of enrolling an adequate number of participants for the trial. Once eligibility is confirmed by both conventional and TCM diagnoses, the patient is entered into the trial and randomly assigned to either a treatment group with formulaic acupuncture based on that TCM diagnosis or a placebo control group. If herbs are being used as part of the treatment, placebo herbs can be easily formulated for the control group. The double screen design is highly rigorous and likely to be acceptable by Western clinical trial standards and more satisfactory from the TCM point of view than trials applying one acupuncture formula to multiple TCM diagnoses.
	 SPECIAL_IMAGE-page0260_0000.svg-REPLACE_ME 
	A variation of the double screen design is to admit into the study all those who meet the Western eligibility criteria and then subdivide participants according to their TCM diagnoses prior to randomization. Within each TCM diagnostic category, patients would be randomized to receive either a formulaic treatment devised for that TCM diagnosis or a control treatment. The formulaic treatment would consist of a core set of points that are common to all categories, with additional formulaic points for that particular diagnostic category.
	Yet another variation of the double screen design permits changing the formulaic treatment within the same patient during the course of the trial. In this application, a variety of formulaic treatments based on the possible TCM diagnoses is developed ahead of time. Then, as the TCM diagnosis of the person changes during the study, the acupuncturist administers a different formulaic treatment that is appropriate for the new TCM diagnosis. This approach moves closer to satisfying the TCM philosophy, which recognizes that there can be variations in the same patient at different time points and not just variations between patients.
1 1.5.2

Can the Modulatory Effects of Acupuncture Prevent Disease?

	Cassidy [51] found that one of the primary reasons people seek acupuncture is for wellness maintenance - a kind of physiological tune-up. Indeed, one of the most appealing principles of TCM is that health is preserved by restoring a state of balance through keeping meridians open and the qi moving freely. It is postulated that TCM can detect minor, subclinical imbalances before they manifest as overt signs and symptoms. Consequently, according to this philosophy, a person is wise not to wait until illness occurs but rather to use acupuncture as preventive care. If this aspect of TCM can be validated, it may be the strongest contribution that this medicine has to offer: health maintenance with enhanced quality of life, well-being, and the absence of disease. The basic question is: can the TCM assertion be validated that subclinical symptoms are detectable and correctable which, if left unchecked, would lead to predictable biomedical symptomology?
	Several studies with animals and humans now document that physiological processes can be normalized by acupuncture (e.g., cardiovascular [52-53], immunological [54], and gastrointestinal [55]). For example, Ballegaard et al. [53] demonstrated that acupuncture has a modulatory effect on cardiovascular indicators including skin blood flow, heart rate, and product of blood pressure and heart rate (increasing low normal values while decreasing high normal values) and concluded there may be value in healthy people using acupuncture to maintain cardiovascular homeostasis. Lao et al. [5] found that postoperative dental patients demonstrated fewer surgical side effects such as swelling and inflammation after acupuncture, also suggesting an anti-inflammatory modulatory effect.
	To assess whether acupuncture can prevent chronic conditions requires costly, longitudinal, long-term epidemiological studies. However, a starting point for examining the effects of acupuncture on prevention can focus on acute conditions. For example, does Chinese medicine given preventively during the flu season lessen the incidence and severity of illness? Does it reduce the incidence of illness in at-risk populations such as the elderly?
11.5.3

Can Acupuncture plus Chinese Herbs Improve Efficacy?

	In contrast to several styles of acupuncture that use needling without herbal therapy notably the Worsely-originated Five Element school, the French energetic style favored by most M. D. acupuncturists, and several systems of Japanese acupuncture the predominant style taught at U. S. acupuncture colleges, practiced by most licensed acupuncturists and known as TCM, fully integrates Chinese herbal therapy into its treatments. However, virtually no clinical trials have assessed the efficacy of acupuncture plus herbs.
	Most Western trials of Chinese herbal therapy have tested either single herbs or isolated components rather than the herbal formulas characteristic in clinical practice. It is ironic that the increasing interest in "complementary" and "integrative" approaches to medicine has resulted in trials of acupuncture 136, 56] or herbs [57-58] as adjunctive to biomedical care but not led to trials of acupuncture plus herbs.
	One expanded research design would randomize patients to groups receiving acupuncture plus herbs or acupuncture plus placebo herbs. When an herbal formula is prepared in tablet form, it is relatively straightforward also to prepare an innocuous placebo, with both sets of tablets having a similar shape, color, and bland coating [59]. Alternatively, an herbal preparation can be prepared in a standardized manner as a decoction (tea), while a similar weight of herbs with no known benefit for the test condition but a smell and taste similar to those of the active herbs can be used for a placebo decoction [60]. Such testing of herbal therapy as adjunctive to acupuncture allows for the possibility of a dose-response curve, a component of pharmaceutical trials rarely attempted in herbal trials.
11.5.4

Can Acupuncture plus Conventional Care Improve Efficacy?

	A second research design involving an active control would compare actual practices of Chinese medicine (either acupuncture alone or acupuncture plus herbs) and biomedicine. Patients selected according to strict inclusion and exclusion criteria would be randomly assigned to receive one or the other type of care. If a condition chosen for study were treatable by biomedicine within a known time course, then such a study would reveal if Chinese medicine is as effective in a similar time period. Additional endpoints, including adverse side effects and cost effectiveness, could be compared for the two types of treatment.
11.5.5

Additional Applications

11.5.5.1

Evaluating Acupuncture Within Its Own Paradigm

	Few trials have asked whether acupuncture is effective for conditions within its own medical paradigm, and few have explored how much additional information can be gained by including Chinese medicine diagnoses as endpoint measures. Among the questions future trials could ask are:
	- Can acupuncture be shown in randomized controlled designs to correct Chinese medicine diagnoses? Can it relieve liver qi stagnation, correct kidney yin deficiency, or balance a condition of "too much fire?"
	- Do Chinese medicine symptoms improve at the same rate as biomedical symptoms? (For example, does tongue coloration return to normal prior to, at the same time as, or after serum enzyme markers return to normative values?)
	- Do patients who respond well or poorly to a biomedical treatment tend to fall preferentially into particular Chinese medicine subgroups?
11.5.5.2

Controlling for Individual Variation in Response to Acupuncture

	In designing and interpreting clinical trials of acupuncture, little attention has been given to the potentially confounding problem of individual variations in responsiveness to treatment. The need to consider this phenomenon has become especially clear in studies of acupuncture analgesia. In animal studies, good responders and poor responders are often identified on the basis of prescreening tests and treated separately when examining the mechanisms of acupuncture analgesia [61-62]. Such studies have shown that individual variations in acupuncture analgesia are closely paralleled by variations in morphine-induced analgesia and analgesia induced by stimulation of the periaqueductal gray (PAG), a midbrain region that plays a key role in the processing of pain signals [63-65]. Further, animals identified as poor responders not only show high levels of cholecystokinin (CCK-8, an endogenous antiopioid neuropeptide) in their PAG but also can be converted to good responders by decreasing their brain levels of CCK-8 [66]. In humans, the existence of responders and nonresponders to morphine analgesia has long been recognized and is often taken into account in the research design of clinical trials [67-68].
	The consequences of individual variations for clinical trials of acupuncture lie in the importance of assessing, for example, whether patients with headaches unresponsive to acupuncture have a vascular or musculoskeletal condition subtype that does not respond well to the treatment and/or have a biochemical makeup that prevents acupuncture from effectively stimulating their endogenous pain regulating mechanisms. In this light, the outcome of a clinical trial may well be a composite of independently varying responses to acupuncture and, as such, can confound interpretation of results. One approach to lessening the impact of individual variation would be to stratify for good or poor responders to acupuncture analgesia prior to randomizing patients into treatment groups. By relying on the high correlation in individual responses to acupuncture and morphine analgesia, patients enrolled in clinical trials of acupuncture efficacy for pain could be classified as good or poor responders on the basis of plasma and urinary markers used to differentiate responders and nonresponders to morphine [69]. The recognition of individual variations should also prompt clinical trials of acupuncture to report individual responses in addition to mean values. With this information, as well as rigorously defined inclusion and exclusion criteria at the outset, the contribution of individual response variations to trial outcome can be more clearly assessed.
11.6

Conclusions

	Future acupuncture research holds many promising possibilities as clinical trials are creatively designed to reflect acupuncture as it is actually practiced. Once the Western and Chinese medical paradigms are brought into the same clinical trial framework, the scope of questions that can be asked is broadened and the potential information gain becomes apparent.
	Acknowledgement. We would like to express appreciation to Victoria Hadhazy for her kind assistance with this manuscript.
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  CHAPTER 12

  Future Directions for Research on the Physiology 
 of Acupuncture

R. Hammerschlag • L. Lao

12.1

Overview

	Clinical research provides a systematic approach for identifying conditions of disease and dysfunction that can be effectively treated by acupuncture; physiological research examines how acupuncture works. Several rationales support the need for these latter studies. Evidence of mechanism imparts credibility to clinical findings of acupuncture as a drug-free alternative for treating conditions involving pain, inflammation, and nausea. Understanding the mechanisms by which needling promotes healing enhances the acceptance of acupuncture in the West, particularly when changes are detected in cells or molecules related to neural, hormonal, immune, cardiovascular, gastrointestinal, and other biomedically defined systems. Biomedical correlates of acupuncture action, in turn, assist researchers in improving the design of trials testing the efficacy of acupuncture treatment.
	It can be argued, however, that the question guiding most mechanism-directed research "What biochemical or physiological changes correlate with acupuncture effectiveness?" is useful but limiting. Equally needed are studies that ask the broader question "What can acupuncture tell us about how the body functions that Western medicine and physiology have not yet discovered?"
	The present chapter examines three fruitful areas for physiological research in acupuncture with the potential for revealing additional biomedical correlates of acupuncture effectiveness and for shedding light on new ways to understand human health and disease. Firstly, we address the need to identify mechanisms of acupuncture analgesia for management of chronic pain. The need for this new direction arises from an anomaly: that acupuncture practitioners most commonly treat chronic pain whereas neurophysiological models of acupuncture analgesia are based mainly on studies of neurologically distinct acute pain. Secondly, we examine a range of techniques used to stimulate acupoints, from electroacupuncture to qigong, to assess the degree of confidence with which we can accept neurophysiologically based models as the predominant means of explaining acupuncture analgesia. Thirdly, we review the concept that, as a treatment system not restricted to pain modulation, acupuncture acts by exerting a normalizing or homeostatic effect on physiological parameters, upregulating hypo conditions while down-regulating hyper conditions. In this context, we consider proposals that view acupuncture as acting on a self-regulatory system, one that may not be fully explainable in terms of currently accepted nervous, endocrine, and immune system functions.
12.2

Acupuncture and Chronic Pain: Models and Mechanisms

	Acupuncture-produced analgesia (AA) is one of the most extensively investigated areas in the field of research directed at the physiology of acupuncture [27, 41, 501. The most common animal behavioral models in AA research challenge acupuncture to lengthen the time that a normal (noninjured) animal will tolerate a transient noxious stimulus. Increased tolerance, measured as an increase in time before the test animal flicks its tail, jerks its head, avoids a hot plate, or vocalizes, is equated with increased analgesia 120, 30, 401. Typically, heat or subcutaneous electrical stimulation is applied to the skin, tail, or nostril region, and the tail-flick latency or "latency to squeak" is measured before and after acupuncture or in needled vs. sham needled animals [20, 411. It has been frequently demonstrated that electroacupuncture (EA) increases response latency to noxious stimuli in animals, indicating that it produces an analgesic effect. These studies have proven valuable in establishing that AA does, in fact, have a physiological basis and that acusignals underlying AA appear to follow neural pathways well-known to researchers who study the neurobiology of pain.
	A major drawback of such studies, however, is their limited clinical relevance. Four lines of reasoning support this argument:
	1. Analgesic effects of EA diminish rapidly after the termination of EA treatment, typically within 10-20 minutes 1201. This provides an inadequate model of common clinical observations of post-treatment effects of AA, at least temporally.
	2. Behavioral tests employed as endpoints in AA studies often require restraining the animals, which in turn may inadvertently cause stress-induced analgesia that can confound the experimental results 139, 541.
	3. The intensity of EA used has often been higher (up to 18 V) than that used in clinical practice [30, 421. This is because the clinically effective use of low intensity electrical stimulation may not be able to increase the pain threshold dramatically in normal animals.
	4. The normal animal model does not resemble the pathological chronic pain conditions that acupuncturists are most often called upon to treat clinically.
	Thus, in spite of numerous AA studies that have revealed considerable details of the physiological bases of acupuncture, many questions regarding clinical applications of acupuncture cannot be answered by examining animal models of acute transitory pain, for example:
	1. What is the "optimal dose" of acupuncture treatment as determined in doseresponse studies (the most appropriate frequency of treatments, duration of a treatment session, and follow-up protocols after the initial concentrated treatments) for a given chronic pain condition?
	2. What is the role of acupuncture in treating underlying conditions that produce pain, such as inflammation or tissue injuries?
	3. How can stress-induced analgesia be minimized in acupuncture studies that involve animal behavioral endpoints?
	To answer these questions, acupuncture needs to be evaluated in clinically relevant, chronic pathological conditions such as an animal model of persistent inflammatory pain.
	Persistent inflammatory pain models have been developed in the rat using inflammatory agents such as yeast, carrageenan, and complete Freund's adjuvant (CFA), which can produce inflammation lasting for hours, days, or weeks [26, 29, 57]. This class of noxious stimuli has recently been employed to develop a rat behavioral model of chronic inflammatory pain for the study of AA [28]. Injection of CFA into the intraplantar surface of the rat's hindpaw produces an intense inflammation characterized by edema, redness, and hyperalgesia that is limited to the injected paw [23, 44, 45]. The hyperalgesia is assessed by exposing the hindpaw to a thermal or mechanical stimulus and monitoring the paw withdrawal latency or the intensity of the stimulus that produces withdrawal [25, 45]. This model provides sufficient time (up to 10 days) to evaluate the post-treatment effects of EA and minimizes stress-induced analgesia by its use of unrestrained animals. This is because, in pathological conditions, lower EA intensities - comparable to those used in clinical practice - can produce desired antihyperalgesic effects. This CFA-mediated persistent inflammatory pain model may also allow the analgesic, antihyperalgesic, and anti-inflammatory effects of acupuncture to be investigated separately, under clinically relevant pathogenic conditions [28].
	Although studies have demonstrated that the mechanism of acupuncturemediated analgesia (AA) is attributable to the release of opioids from the central nervous system, clinically effective local acupuncture points, adjacent to the painful area, are often crucial for the treatment of musculoskeletal pain conditions [11, 37]. The effectiveness of using local acupuncture points to treat musculoskeletal conditions such as osteoarthritis has also been demonstrated in clinical trials [5, 14]. One question arising from these studies concerns to what extent peripheral mechanisms underlie the effectiveness of acupuncture. Recent studies have revealed that, in addition to a central opioid system, a peripheral opioid system exists which is also involved in modulating pain, particularly localized inflammatory pain [43, 511. Zhang et al. [62] recently reported that AA is partially blocked by local application of naloxone, suggesting that peripheral opioids are released following electroacupuncture treatment. Additional studies are needed in this new direction of AA research not only to investigate further the physiological mechanisms induced by the needling, but to provide information that can improve the clinical practice of acupuncture.
12.3

Invasive and Noninvasive Stimulation of Acupoints: Implications for Mechanisms

	Clinical practice as well as clinical trials have demonstrated that acupoints can be stimulated by a wide range of procedures. These modes of stimulation include the minimally invasive techniques of electroacupuncture and manual needling as well as noninvasive techniques involving surface contact, as with transcutaneous electrical nerve stimulation (TENS) electrodes, and noncontact, as with the practice of external qigong. (Pressure and lasers are among an array of additional means that are not included in this discussion.) The most intense form of acupoint stimulation is usually achieved via electroacupuncture, involving the mechanical effects of needling augmented by electric current delivered through the needle. When delivered at the same frequencies as electroacupuncture, TENS can, under some conditions, produce com parable effects [13, 33). Manual needling alone, whether with the deeper, intramuscular techniques favored by Chinese-style practitioners or the relatively shallow, subcutaneous needling preferred in the Japanese style, involves mechanical effects of the needle often enhanced by the practitioner's intent (yi, in Chinese medical terminology). A more subtle form of acupoint stimulation is achieved in toyo hari acupuncture, with the needle placed either just touching the acupoint at the skin surface or held directly above the acupoint without skin contact and with the practitioner sensing or projecting qi (ki in Japanese) through the needle [6, 181. Finally, qigong practitioners typically stimulate acupoints by projecting their qi at a distance from the patient [24, 47).
	Viewed in this manner, where the mode of acupoint stimulation varies from electrical current to mechanical activity to the undefined transmission of qi, several questions arise with regard to the neurobiology-based models of AA elegantly described in the earlier chapters of Han, Pomeranz, and Takeshige.
	How well do these models, derived predominantly from studies employing strong electrostimulation techniques, hold up when manual needling is employed? With very few exceptions, e.g., the first demonstration in humans that naloxone partially inhibits acupuncture analgesia induced by manual needling [34], virtually all the evidence for the acupuncture-endorphin connection has been derived from studies using electroacupuncture. From a research perspective, electroacupuncture (as well as TENS) has an obvious advantage over manual acupuncture in that defining the frequency, amplitude, duration, and wave form of electrostimulation allows experiments to be reproduced with a greater degree of confidence than do descriptions of twirling, thrusting, and other traditional techniques of manual stimulation.
	From a clinical perspective, electrostimulation parameters for acupuncture analgesia have been chosen for their effectiveness in reproducing therapeutic outcomes of different styles of manual needling. For example, high frequency (100Hz) and low frequency (2 Hz) electroacupuncture are described as mimicking traditional needling techniques known as "dense" and "disperse," respectively 1101. However, systematic studies are needed to test whether disperse needling preferentially induces nervous system release of enkephalin and (3-endorphin similar to that under 2-4 Hz electrostimulation (via needles or TENS) and whether dense needling preferentially releases dynorphin and serotonin similar to that with 100-200 Hz electrostimulation (12, 21, 22]
	Does Japanese style shallow needling stimulating cutaneous afferent nerve endings release the same endogenous substances as Chinese style deep needling, which predominantly stimulates muscle afferents? While no clinical trial has been designed to cony pare these two types of needling performed by practitioners trained in the respective traditional medicine, several trials have inadvertently approximated this design by performing shallow needling on the "control group" at the same acupoints used for deep needling of the "acupuncture group" [ 19, 58]. It is clearly inappropriate to assess the magnitude of acupuncture efficacy relative to sham needling in a trial where, in fact, two different styles of acupuncture are compared. Clinical trials of deep vs. superficial needling would be of value if clinical effectiveness and corresponding release of endogenous opioids were compared. A related issue is to assess clinical effectiveness and patterns of neurochemical release under conditions where deep needling, which elicits patient reports of de qi sensations (often claimed by tra ditional Chinese acupuncture as essential to produce clinical results), is compared to Japanese style shallow needling, where practitioners treat with no attempt to elicit this sensation.
	Do noninvasive toyo hari needling and external qigong also release endogenous opioids as they clinically suppress pain? Clinical reports of pain modulation resulting from nonpuncture and noncontact treatment at acupoints are not readily explainable within the framework of neurobiological models of acupuncture analgesia. In such models, electrical signaling along peripheral and central nerve pathways is initiated predominantly by physical contact between the acupuncture needle and mechanoreceptive nerve endings in skin and muscle. While these models can be expanded to include nonpuncture initiating stimuli such as pressure (acupressure) and electrical fields (TENS), there is no generally accepted understanding of what types of stimuli are generated during toyo hari noncontact needling and external gigong treatment, nor is there direct evidence that such practices stimulate the same neural pathways proposed for electro- and manual acupuncture. Of considerable interest, however, is that the propagating sensations along the meridians, reproducibly reported by sensitive subjects in response to manual needling at single points [59], has also been reported in response to noninvasive toyo hari needling [7] and external gigong [24].
	Several types of research studies are needed to begin examining the phenomena of acupoint stimulation at a distance in relation to invasive needling techniques. Randomized clinical trials comparing electroacupuncture, manual acupuncture, toyo hari needling, and external gigong should be designed to assess (a) pain modulation, (b) endogenous opioid release, and (c) direct microelectrode recording from single nerve fibers [551. These latter experiments in human subjects have demonstrated similar neural activity patterns in response to manual acupuncture with and without electrostimulation. Clearly, it is also important to identify the nature of the signal passing from the toyo hari or qigong practitioner to the acupoint. Preliminary studies suggest that electromagnetic [36, 49] and microwave [ 15] emissions detected from the palms of practitioners may be involved
12.4

Bidirectional Effects of Acupuncture

	A clinically recognized but little-researched phenomenon of acupuncture is its ability to induce bidirectional effects such that needling at the same acupoint(s) can return a particular physiological parameter, e.g., heart rate, gastric acid secretion, or antibody levels from a hypo- or hypercondition to normative levels. For example, blood pressure and heart rate in strains of rats bred to be either congenitally hypotensive or hypertensive were "normalized" by acupuncture [611. Pharmacological studies suggest that the pressor effects of acupuncture in hypotensive rats, being naloxoneinsensitive but attenuated by scopolamine, involve central cholinergic mechanisms, whereas the depressor effects in the hypertensive animals, being inhibited by naloxone or parachlorophenylalanine, are mediated by the release of endogenous opioids and serotonin. Similar normalizing effects of acupuncture have been described in rats made hypotensive by withdrawing blood [52]and in dogs made hypertensive by intravenous infusion of epinephrine [311.
	In light of the evidence supporting a homeostatic action of acupuncture, it is not surprising that studies on cardiovascular function in normal human subjects have shown only slight or nonsignificant effects on heart rate or blood pressure when the data was presented in mean values [35, 53]. However, a different picture emerges when the effects on individual subjects are analyzed. A trial involving electroacupuncture at L1.4 and LI.I O [ 1 ] revealed that individuals whose pretreatment heart rates were in the lowest third of the normal test group had their rates increased by acupuncture, whereas those with initial values in the highest third experienced a decrease. Similar bidirectional effects were observed for cutaneous blood flow and the product of blood pressure and heart rate. Had these sets of data been analyzed as mean effects, none of the results would have been statistically significant.
	Indications of the normalizing or balancing effect of acupoint stimulation have also been detected in immune system responses. In healthy human subjects, the levels of IgA (the main class of salivary immunoglobulins) increased after 30 minutes of acupuncture (LI.4, St.7, endocrine ear point) and at 24 hours post-treatment in individuals whose initial levels were low and decreased in those whose initial levels were high [60]. While the effects of acupuncture have been examined on a wide range of other immune responses, including cell-mediated (white blood cell levels, macrophage phagocytic activity, T cell proliferation and transformation, and natural killer cell cytotoxic activity) and humoral immunity (competency of B-cells to engage in antibody production) [9, 16, 17, 48], only the IgA study cited above was designed to examine the bidirectional effects of acupuncture.
	While the logic of biomedicine is to monitor specific cellular and molecular biomarkers in response to acupoint needling, this approach causes acupuncture to be regarded as a set of finely tuned procedures that, similar to pharmacologically designed drugs, selectively affect different cell populations. An arguably more useful physiological model is to consider acupuncture as facilitating the release and balancing the circulating levels of the same endogenous substances, e.g., cytokines and endogenous opioids, that immune system cells use to communicate with each other as well as with cells of the endocrine, nervous, and other regulatory systems [8, 38, 56]. In a body that has lost the ability to regulate one of its systems, biomedicine prescribes an agonist or antagonist drug that mimics or blocks the action of an inadequately functioning regulatory molecule. In contrast, acupuncture may stimulate a regulatory system in a manner that induces self-correction mechanisms.
	What is needed are systematic studies of the bidirectional effects of acupuncture, with multiple measurements of regulatory or affector molecules, such as the cytokines, as well as affected cell and molecular markers. Only with this broader approach can questions be framed and answers sought as to how acupuncture regulates internal activities. As the data accumulates, it should become clearer whether the homeostatic actions of acupuncture are initiated directly via known neural and hormonal mechanisms, as occurs when a drug binding to its target receptor initiates a cascade of events. Alternately, it may also become clearer that acupuncture triggers homeostatic regulation by acting on an integrative system that is separate from but interfaces with the known autonomic and humoral systems [4, 32].
	What clues do we have in the search for such an integrative system? If, as briefly discussed earlier in this chapter, the clinical effectiveness of toyo hari and external qigong treatments-at-a-distance are mediated by bioelectromagnetic (BEM) field effects, the question arises whether these fields, externally applied to acupoints, have informational content. It has long been recognized that electromagnetic fields of brain, muscle, and heart give rise to EEG, EMG, and EKG patterns that contain diagnostic information. Only recently has it also been observed that living organisms emit BEM radiation as biophotons that contribute to the regulation of a range of cell biological events from membrane transport to gene expression [46]. The question to be explored is whether "energy" practitioners have learned to transmit this form of BEM field as a therapeutic signal. The intriguing possibility is that practitioner-generated weak electromagnetic fields may entrain or "pattern-correct" abnormal BEM fields within the body [2].
	There is promising evidence that such BEM fields arise from the direct current generated by cells that surround neurons [3]. The nature of this DC phenomenon, the possible role of acupoint stimulation in the maintenance of the BEM field integrity, and the manner in which the BEM field acts via stimulation of acupoints to regulate energetic, molecular, and cellular events are highly exciting directions for future research.
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