|How does it work?
DOES ACUPUNCTURE REALLY WORK?
Yes. In the past 4,500 years, more people have been successfully treated with acupuncture than with all other health modalities combined. Today acupuncture is practiced widely in Asia, the former Soviet Union, and in Europe. It is now being used more and more in America.
Acupuncture treatments can be given at the same time that other techniques are being used, such as conventional Western medicine, osteopathic or chiropractic adjustments, and homeopathic or naturopathic prescriptions.
DOES THE PATIENT HAVE TO BELIEVE IN ACUPUNCTURE FOR IT TO WORK?
No. Acupuncture has been used to successfully treat cats, dogs, horses and other animals in a number of well-documented veterinary acupuncture studies. These animal patients do not understand or believe in the process that helps them get better.
Illustration of acupuncture points on the body of a horse from
Ma Niu Yi Fang, a Chinese veterinary textbook written in 1399.
A positive attitude toward wellness may reinforce the effects of the treatment received, just as a negative attitude may hinder the effects of acupuncture or any other treatment. A neutral attitude ("I don't know if I really believe in this.") will not block the treatment results. One study (Moore & Berk 1976) assessed the effect of positive versus negative settings for acupuncture and found no difference. They also tested hypnotic suggestibility in terms of pain reduction, but again found no significant correlation with response to acupuncture treatment. Being more or less susceptible to hypnosis has no relation to one’s responsiveness to acupuncture treatment.
WHAT ARE THE MECHANISMS OF ACUPUNCTURE?
The classical Chinese explanation is that there are channels of energy (qi or ch'i) that form regular patterns throughout the body. These energy channels, called “meridians,” are like rivers flowing through the body to irrigate and nourish the tissues. An obstruction in the movement of these energy rivers is like a dam that backs up the flow in one part of the body and restricts it in others. Needling or otherwise stimulating the acupuncture points can influence the meridians. The needles help unblock the obstructions and re-establish the regular flow through the meridians. By harmonizing the flow of energy in the meridians, acupuncture can help correct imbalances in many of the body’s systems, including the internal organs.
The modern scientific explanation is that needling the acupuncture points stimulates the nervous system to release chemicals in the muscles, spinal cord, and brain, including endorphins, enkephalins and other neurotransmitters. These chemicals will either change the experience of pain, or they will trigger the release of other chemicals and hormones which influence the body's own internal regulating system, bringing about a normalizing effect on neuroendocrine function. The improved energy and biochemical balance produced by acupuncture results in stimulating the body's natural healing abilities, and in promoting physical and emotional well-being.
(National Institutes of Health, 1997): “Many studies in animals and humans have demonstrated that acupuncture can cause multiple biological responses. These responses can occur locally, i.e., at or close to the site of application, or at a distance, mediated mainly by sensory neurons to many structures within the central nervous system. This can lead to activation of pathways affecting various physiological systems in the brain as well as in the periphery. A focus of attention has been the role of endogenous opioids in acupuncture analgesia. Considerable evidence supports the claim that opioid peptides are released during acupuncture and that the analgesic effects of acupuncture are at least partially explained by their actions. That opioid antagonists such as naloxone reverse the analgesic effects of acupuncture further strengthens this hypothesis."
Regarding stimulation by acupuncture, the NIH report also writes:
- “Acupuncture may activate the hypothalamus and the pituitary gland, resulting in a broad spectrum of systemic effects.
- “Alteration in the secretion of neurotransmitters and neurohormones and changes in the regulation of blood flow, both centrally and peripherally, have been documented.
- “There is also evidence of alterations in immune functions produced by acupuncture. Which of these and other physiological changes mediate clinical effects is at present unclear.
- “Findings from basic research have begun to elucidate the mechanisms of action of acupuncture, including the release of opioids and other peptides in the central nervous system and the periphery and changes in neuroendocrine function. Although much needs to be accomplished, the emergence of plausible mechanisms for the therapeutic effects of acupuncture is encouraging.”
One of the studies cited by the NIH was conducted by Abass Alavi, M.D., chief of nuclear medicine at the University of Pennsylvania Medical Center, who showed that acupuncture affects the flow of blood in the brain. He used SPECT (single photon emission computed tomography) to view the brains of four people with pain and five pain-free people who served as the control group. Dr. Alavi found that after acupuncture needles were inserted, all of the patients had increased blood flow to the thalamus, the area of the brain that relays pain and other sensory messages. Because the brains of the pain-free group showed the same reactions as those with pain, the changes in blood flow couldn’t be attributed to placebo.
PET-Scans of the brain during acupuncture: University of California Irvine professor and physicist Zang-Hee Cho, a member of the highly respected National Academy of Science, the inventor of an early version of the Positron Emission Tomograph, or PET scan, and a pioneer of the MRI scanner, both of which have revolutionized our ability to see into the body and brain, found that stimulation of the vision-related acupoint showed the same reaction in the brain as stimulation of the eye. As the acupuncture signal passes to the brain via nerves, it possibly stimulates the hypothalamus, the “executive center” of the brain, responsible for the production and release of hundreds of neurochemicals, Cho said.
Acupuncture: pain management coupled to immune stimulation (Gollub, 1999): “The phenomenon of acupuncture is both complex and dynamic. Recent information demonstrates that acupuncture may exert its actions on pain and immune processes. The coupling of these two systems occurs via common signaling molecules, i.e., opioid peptides. In this regard, we surmise that
- opioid activation leads to the processing of opioid peptides from their precursor, proenkephalin, and
the simultaneous release of antibacterial peptides contained within the precursor as well. Thus,
central nervous system pain circuits may be coupled to immune enhancement.
- Furthermore, acupuncture needle manipulation elicited signal increases bilaterally in the region of the primary and secondary somatosensory corticies in human brain as determined by magnetic resonance imaging.
- The maps reveal marked signal decreases bilaterally in multiple limbic and deep gray structures including the nucleus accumbens, amygdala, hypothalamus, hippocampus, and ventral tegmental area.
- Taken together, we surmise a major central nervous system pathway as well as local pain and immune modulation during acupuncture.”
(Fu, 2000): “In recent years, more and more laboratory proof has accumulated that acupuncture can
- change the charge and potential of neurons,
- the concentrations of K(+), Na(+), Ca(++) and
- the content of neuro-transmitters such as aspartate, and taurine and the quantities of neuro-peptides such as beta-endorphin and leu-enkephalin.
- All these phenomena are directly related to nerve cells.”
(H. Fu, Med Hypotheses (2000) 54: 358-9)
Immune System effects of Acupuncture: “The following changes were found in the TCM group: within the lymphocyte subpopulations the CD3+ cells (p = 0.005) and CD4+ cells (p = 0.014) increased significantly. There were also significant changes in cytokine concentrations: interleukin (IL)-6 (p = 0.026) and IL-10 (p = 0.001) decreased whereas IL-8 (p= 0.050) rose significantly. Additionally, the in vitro lymphocyte proliferation rate increased significantly (p = 0.035) while the number of eosinophils decreased from 4.4% to 3.3% after acupuncture (p > 0.05). The control group, however, showed no significant changes apart from an increase in the CD4+ cells (p = 0.012).” (Joos, : J Altern Complement Med. 2000 Dec;6(6):519-25)
Difference between Manual and Electro Acupuncture (Kong, 2002):
“Results showed that electroacupuncture mainly produced fMRI signal increases in precentral gyrus, postcentral gyrus/inferior parietal lobule, and putamen/insula; in contrast, manual needle manipulation produced prominent decreases of fMRI signals in posterior cingulate, superior temporal gyrus, putamen/insula. These results indicate that different brain networks are involved during manual and electroacupuncture stimulation. It suggests that different brain mechanisms may be recruited during manual and electroacupuncture.”
Effects of Acupuncture on the Musculoskeletal System
Acupuncture can strengthen tendons and ligaments, stimulate Golgi receptors and muscle spindles, deactivate trigger points, treat overactive motor points, provide blood and growth factors to hemodynamically disturbed tissues (commonly seen in myofascial pain syndromes), reset motor points and neural control (possibly including replacement of oversensitive tissues with less sensitive microscars), and stimulate other reflex mechanisms.
Strengthen Tendons & Ligaments
Needling may strengthen soft tissues such as tendons and ligaments by inducing a local inflammatory reaction:
- The mechanical trauma that results from needling may injure cells, including mast cells and vessels.
- Blood products (such as platelet growth factors and transforming growth factor beta) spill and activate healing.
- Amines and other mediators of inflammation are set free or are newly-formed locally, generating an acute inflammatory reaction.
- Plasma seeps into the tissues, possibly allowing blood to reach poorly-vascularized areas such as ligaments and tendons. After a delay of a few hours, the plasma begins to attract polymorphs. In the absence of significant bacterial infection, this leukocytic infiltration is mild and fades quickly.
- Macrophages migrate into the area of inflammation and work to remove red blood cells, fibrin, dead polymorphs and other cellular material. At the same time, with granulocytes, the macrophages work to activate fibroblasts.
- Local fibroblasts begin to hypertrophy and to generate collagen and elastic fibers. If foreign matter such as an injection of pomess (flower) solution is left in place, (or acupuncture suture burial—a
TCM surgical technique) it causes a foreign matter response. This response, which includes invasion of giant cells and a strong fibrous reaction, adds strength to the tissue.
Stimulate Golgi Receptors & Muscle Spindles
Many acupuncture points are based on nerve arrangement. According to Gunn, two types are in muscles, principally in motor points and Golgi tendon organs (Gunn 1977). Rotation of a needle in hypertonic muscle tissues can tug on muscle fibers, not unlike the way thread rolls on a spool. This action seems to stimulate stretch-sensitive Golgi receptors and muscle spindles, which may account for the resulting muscle relaxation.
Deactivate Trigger Points
Muscle needling may provide blood products and wash away sensitizing substances, brake fibrotic tissue that have entrapped nerve endings, and/or replace hyperactive nociceptors with nonpainful microscars. Travell has reported that active myofascial trigger points can be treated with "dry needling". This also results in muscle relaxation, which reduces mechanical stress on tissues such as tendons, thereby allowing more effective healing.
Jessen et al. (1989) remarks that, even in trigger point injection, the most important factor may not be the injected substance; rather, it may be the mechanical effects of needling on the abnormal tissue and interruption of the trigger point's mechanism, if one has developed.
Treat Overactive Motor Points
Muscle motor points are points that are packed densely with sensory end-organs, causing muscle to be easily excitable and most liable to tenderness. In his writings on the relationship of motor points to acupuncture points and on their sensitivity to pain, Gunn (1976,1979) says that the practitioner can needle motor points to treat muscular pain and tension. The proposed mechanism is similar to that of needling techniques in other muscle tissues. Gunn postulates that growth factors released by injured cells and platelets also result in healing of mildly-demyelinated nerves.
Provide Blood & Growth Factors
Chronic muscle tension and spasm can cause reduced oxygen and other nutrient supply. This, in turn, can result in a small area of abnormal function and ectopic muscle facilitation. Bleeding, which can be an effect of needling, can break microscars in these areas, and can provide blood and growth factors to facilitate healing.
Alter Neural Control
Needling may alter neural control:
- By neurotransmitter and endorphin stimulation.
- By reflex action such as stimulation of inhibitory fibers by a fusimotor mechanism.
- By saturation of joint receptors. Stimulate Reflex Mechanisms
Needling cutaneous and other tissues can stimulate various spinal reflexes and serotinergic descending inhibitory systems (see chapter 2). Periosteal acupuncture techniques (Lawrence 1987) are believed to regulate sympathetic fibers in and around the periosteum, increasing blood circulation in the area.
A Closer Look at the Neurological Mechanisms of Acupuncture
Acupuncture points have been described as 2-8mm, cylindrical shaped, perforations within superficial fascia in which a neurovascular bundle runs (Heine 1988). They are intimately related to the distribution of nerve trunks, motor endplates and blood vessels (Dung 1984; Gunn ibid; Chan 1984). Kellner (1966) has shown two types of acupoints, receptor and effector, by histological studies. Therefore, acupuncture effects are closely related to the nervous system and achieved by complex mechanisms which integrate peripheral, ascending, descending and higher centers in the nervous system.
The mechanisms of acupuncture's effects are thought to be largely neurochemical and neurophysiologic.
The fact that acupuncture analgesia can be transferred from a treated animal to a non-treated animal (Han 1992) by cross-circulation and CSF infusion to ventricles supports the hypothesis of a systemic neuropharmacologic effect.
Early reports on the analgesic mechanism of acupuncture involved opioid systems. These reports may have contributed to, and at least supported, the discovery of the endorphin systems (Han 1986). In 1975, the year endorphins were discovered, David Mayer documented that acupuncture affects the opioid system in his demonstration that, in humans, naloxone can block acupuncture analgesia. (N.B. Naloxone is a chemical that can block opioid receptors.) Naloxone has also been shown to block the analgesic effect of acupuncture on dental pain (the affects are influenced by dexamethasone levels), (Mayer, Price and Rafii 1977).
The newly discovered orphanin (opioid peptide) seems to have antagonistic effects on electroacupuncture analgesia (Han 1998).
The analgesic effects of acupuncture can be enhanced by D-phenylalanine and D-leucine, which enhance met-enkephalin degradation (Ehrenpreis 1985; Han 1991), or by bacitracin (Zhang, Tang and Han 1981). (N.B. Bacitracin is a peptidase inhibitor, the injection of which results in increased neuropeptides. Met-enkephalin degradation results in a net gain in opioid-like chemicals). In a review, Pomeranz et al. (1977) concluded that acupuncture analgesia implicates the pituitary endorphins. They postulate that this is so, because placebo acupuncture is not as effective, the analgesic effect of acupuncture can be eliminated by ablation of the pituitary gland, and that naloxone is effective in blocking the analgesic effects of acupuncture.
Non-opioid systems are affected by acupuncture:
- Serotonin (5-HT), norepinephrine,
GABA, calcium and magnesium ions, and secondary central cyclic nucleotides (Han 1987), and acetylcholine have been implicated in acupuncture analgesia (Guan, Yu, Wang and Liu 1986).
- Dopamine is implicated in inhibition of
acupuncture analgesia (Patterson 1986).
- Anti-inflammatory effects have been elicited by stimulation of 17-hydroxycorticosterone, ACTH and cortisol secretion (Ying 1976; Omura 1976; O'Connor 1981).
- Inflammatory mediators can affect pain perception as beta-endorphin levels can be affected by ACTH. This is because ACTH can antagonize the enzyme cleavage from a large, precursor, proopiomelancortin (Smock and Fields
1980). Sin has summarized these anti-inflammatory effects of acupuncture (Sin 1984)
Neurophysiologic & Other Mechanisms
Neurophysiologic mechanisms involve sensory nerves stimulated at the acupuncture point. The afferent systems seem to be important in acupuncture analgesia, and needle sensation (De Qi) is required for successful treatment of pain (Han ibid). Preacupuncture local anesthesia, of subcutaneous and muscle tissue, abolishes the needling sensation and acupuncture's analgesic effects (Chiang et al. 1973). This suggests that receptors within the muscle are responsible for the De Qi sensation, probably do to A-beta and A-delta fibers (Pomeranz and Paley 1979; Wang, Yao, Xian and Hou 1985).
Low threshold large diameter mechanoreceptors situated in the skin, muscles, tendons and joints are activated by innocuous stimuli that may activate the "gate control" mechanism. Acupuncture stimulates A-beta and A-delta (small and medium) fibers which enter the spinal cord and arrive at the medial and lateral portions of the dorsal horn. A-beta fibers terminate in the nucleus propius and in more ventral regions of the dorsal grey matter. A-delta fibers terminate in the marginal zones of the dorsal grey matter, the ventral portion of lamina II and throughout lamina III and inhibit dorsal horn cells at laminae I and V (Yaksh and Hammond 1982; Dorman and Gage 1982).
Analgesic effects that result from stimulation of small, myelinated fibers are transmitted both segmentally and bilaterally (Chiang et al. 1973, 1975). C-fibers do not seem to contribute significantly and application of capsicum, which selectively blocks C-fibers, does not affect acupuncture analgesia (Yu, Bao, Zhou and Han 1978).
The thalamus is thought to be the most important component responsible for the processing of pain impulses and/or integration of pain sensation. The centromedian nucleus of the thalamus, the rephe magnus nucleus, and the arcuate nucleus seem to be the main areas related to acupuncture analgesia (Zang 1980; Hamba and Toda 1988; Yin, Duanmu, Guo and Yu1984). Peripheral stimulation of an acupuncture point was observed to stimulate thalamic neurons with a similar pattern in a cat (Liner and Van Atta 1975).
Descending & Ascending Tracts
Innocuous stimulation of peripheral nerves may excite descending inhibitory serotinergic tracts that then can inhibit nociceptors (Bowsher 1991). The descending dorsolateral funciculus of the spinal cord seems to be involved in acupuncture analgesia. Lesions made at T1-T3 levels resulted in complete abolition of acupuncture analgesia (Shen, Tsai and Lan 1975). Lacerating the contralateral anterolateral columns eradicated the analgesic effect from stimulation of St-36, whereas, laceration of the dorsal column at the level of T12-L1 or superficial lateral cordectomy did not affect acupuncture analgesia (Chiang et al. 1975). Cephalically, impulses produced by acupuncture analgesia are believed to be transmitted through the extralemniscal system (a bundle of sensory fibers in the medulla and pons), then to the thalamus and the sensory cortex.
Convergence of Visceral & Somatic Innervation
Experimental data that demonstrates the existence of convergence of visceral and somatic innervation in laminae V-VII may support the rationale for use of many manual and acupuncture therapies in somatovisceral and visceral-somatic pain. Electrical stimulation of the skin (acupuncture points) has been shown to influence nerves within gray matter (Selzer and Spencer 1969), and so may influence visceral function. Moreover, visceral pain has superficial receptive fields (irritation zones that can be mistaken for musculoskeletal pain) that can be activated by noxious and innocuous stimulation, and by muscle activity beneath the skin (Forman and Ohata 1980; Cervero 1982). Stimulation of acupuncture points at superficial receptive fields may provoke a reflex mechanism that may explain the empirical data about the effectiveness of acupuncture. Reflex mechanisms may also explain why the use of distal acupuncture points affects visceral pain.
The Autonomic Nervous System
Most authors agree that acupuncture points posses lower skin impedance (Kho and Arnold 1997). Electrical skin resistance (impedance) can be demonstrated and measured using simple devices. Many diagnostic instruments used in acupuncture measure skin impedance for the purpose of diagnosing, treating, and following treatment results. Increased pseudomotor activity (increased perspiration from sympathetic activity) lowers skin impedance, which has been documented over injured areas and in segmental distributions (including from visceral disease), (Korr et al. 1962). Acupuncture diagnostic devices use this information in the selection of channels and points to be treated. However, the reliability of these instruments is questionable for various technical difficulties, and because the act of measuring (which passes an electrical charge through the skin) actually changes the impedance.6
Acupuncture points on the Urinary Bladder, upper Stomach and Large Intestine channels are in close proximity to the sympathetic ganglia, stimulation of which may affect the autonomic nervous system.
Using thermography, acupuncture's effect of increasing skin temperature locally, contralaterally, and in other regions has been documented (Lee and Ernst 1987, 1983; Ernst and Lee 1985). Ernst and colleagues have demonstrated long-lasting warming effects, as well. In some instances the temperature distribution was in a craniocaudal gradient, which they speculated was mediated by the reticular formation via the activation of diffuse noxious inhibitory controls on the convergent cells of the dorsal horn. Liao and Liao (1985) have demonstrated that stimulation of acupoint St-36 affected the leg of a stroke patient: producing a small temperature increase in the normal leg and a marked increase in both hands.
The circulatory effects and the decrease of hypersympathetic activity in pain patients is probably one of acupuncture's most important clinical effects.
6. The instrument applies electrical charge across the skin in order to measure skin residence. This can change the properties and resistance of the skin. Some newer instruments may be more reliable.
Sabolovic and Michon have found stimulation of T and B lymphocytes by acupuncture (Sabolovic and Michon 1978). By influencing met-enkephalins, acupuncture can increase T lymphocyte rosette formation from human T lymphocytes (Wybran et al. 1979). Acupuncture has been shown to increase beta-globulins, gamma-globulins, lysozymes, agglutinins, opsonins and complement (Dragomirescu et al. 1961). Acupuncture influences beta-endorphins and met-enkephalins, both of which may enhance natural killer cell activity (Matthews et al. 1984).
Several electrical and electromagnetic theories have been proposed. Robert Becker associated cellular polarity and DC currents with growth, healing and regeneration of tissues, including articular cartilage (Becker and Marino 1982; Becker 1972). Burr (1972) suggested that all events in the body generate electro-dynamic fields, The bioelectrical homeostasis and its relation to acupuncture was reviewed by Zukauskas et al. (1988) and Zhu Zong-Xiang (1981).