The purpose of this study was to examine in man the analgesic effect of non-segmental electroacupuncture (EA) limited to a single point (Hoku hand point) and the influence of naloxone using an original modified electrical dental pain test. Results in the literature are still contradictory as to the degree and specificity of acupuncture analgesia and its opioid nature. Acupuncture techniques as well as experimental pain models are factors accounting for the discrepancies in the results. For this reason, we designed an experimental pain test characterized by a high degree of specificity, validity and reliability. We chose optimal conditions for eliciting specific acupuncture effect, i.e. non-segmental, low frequency and painful intensity range. A cross-over repeated measure experimental design was used. Five normal trained subjects participated in 65 sessions under four conditions (control, EA, EA+naloxone, EA+placebo). Changes in experimental dental pain thresholds served as indices of analgesia. The results indicated a 27% pain threshold increase after 30 minutes of EA stimulation (p<.0001), with no differential effect between pain detection (mild pain sensation) and pain discomfort (strong pain sensation). This increase was partially blocked by the double blind injection of 0.8mg naloxone IM (p<.005). The experiment was designed in such a way as to prevent the occurence of a stress analgesic effect. The endogeneous opioid system was shown to be partially involved in acupuncture analgesia. Other mechanisms of action are discussed in view of the literature findings.
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References
1.
OmuraY. : Electro-acupuncture: its electrophysiological basis and criteria for effectiveness and safety - part I. Acupuncture & Electrother. Res. Int. J., 1, 157–181, 1975.
2.
Shangai Acupuncture Anesthesia Coordinating Group Acupuncture Anesthesia: An anesthesic method combining traditional medicine and western medicine. Chin Med J 1:13–27, 1975.
3.
FoxEJMelzackR. : Transcutaneous electrical stimulation and acupuncture: comparison of treatment for low-back pain. Pain2:141–148, 1976.
4.
LevineJDGormleyJ and FieldsHL. : Observations on the analgesic effects of needle puncture (acupuncture). Pain2:149–159, 1976.
5.
OmuraY. : Pathophysiology of acupuncture treatement: effects of acupuncture on cardiovascular and nervous systems - I. Acupuncture & Electrotherapeut. Res. Int. J.,1, 51–141, 1976.
6.
ChenGSHwangYCSongSJ. : Long-term effect of acupuncture therapy on headache. Amer J Acupuncture6:23–32, 1978.
7.
OmuraY. : Editorial. No invasive circulatory evaluation. Electroacupuncture and TES treatment of diseases difficult to treat in Western Medicine - I (of normal brain circulation and blood pressure. Cephalic hypertension or cephalic hypotension and their related condition - headache, insomnia, blindness due to macula degeneration and retinitis pigmentosa and some psychiatric problems). II (severe low extremity circulatory disturbances, with intractable pain, intermittent claudication, ulceration and thrush or severe diabetic neuropathy). Acupuncture & Electrotherap. Res. Int. J., 8, 177–255, 1983.
8.
ChapmanCRChenACBonicaJJ. : Effects of intra-segmental electrical acupuncture on dental pain: evaluation by threshold estimation and sensory decision theory. Pain3:213–227, 1977.
9.
HolmgrenE. : Increase of pain threshold as a function of conditioning electrical stimulation. An experimantal study with application to electroacupuncture for pain suppression. Am J Chin Med3:133–142, 1975.
10.
MayerDJPriceDD and Rafii-A. : Antagonism of acupuncture analgesia in man by the narcotic antagonist naloxone. Brain Res 121:368–372, 1977.
11.
PomeranzBChengRLawP. : Acupuncture reduces electrophysiological and behavioral responses to noxious stimuli: pituitary is implicated. EXP Neurol54:172–178, 1977.
12.
HanJSLiSJTangJ. : Tolerance to electroacupuncture and its cross-tolerance to morphine. Pharmacology20:593–596, 1981.
13.
SijaL.JianTJishengH. : The implication of central serotonin in electroacupuncture tolerance in rats. Scientia Sin25:620–629, 1982.
14.
SjolundBTereniusLEriksonM. : Increased cerebrospinal fluid levels of endorphins after acupuncture. Acta Physiol Scand100:382–384, 1977.
15.
OmuraY. : Editorial. Pain threshold measurement before and after acupuncture: controversial results of radiant heat method and electrical method. The role of ACTH-like substances and endorphins. Acupuncture & Electrother. Res. Int. J. 3, 1–21, 1978.
16.
ChapmanCRBenedettiCColpitisYHGerlachR. : Naloxone fails to reverse pain thresholds elevated by acupuncture: acupuncture analgesia reconsidered. Pain16:13–31, 1983.
17.
DworkinBRLeeMHLZaretskyHHBerkeleyHA. : Instrumentation and techniques. A precision tooth-pulp stimulation technique for the assessment of pain. Behav Res Meth Instrum9:463–465, 1977.
18.
WolffB.B. and HorlandA.A. : Effect of suggestion upon experimental pain: a validation study. J. Abn. Psychol., 72.43-56.1967.
19.
Academy of Traditional Chinese Medicine. An outline of Chinese accupuncture: Foreign language press. Peking,1975, PP 305.
20.
TodaKIchiokaM. : Electroacupuncture: relations between forelimb afferents impulses and suppression of jaw-opening reflex in the rat. EXP Neurol61:465–470, 1970.
21.
KeppelG. : Design & Analysis; a Research Handbook. Prentice-Hall, Inc., 1982, (a) pp. 276–332, (b) pp. 150–151.
22.
ChapmanCRWilsonMEGehrigJD. : Comparative effects of acupuncture and transcutaneous electrical stimulation of the perception of painful dental stimuli. Pain 2:265:283, 1976.
23.
LynnBPerlER. : Failure of acupuncture to produce localised analgesia. Pain3:339–351, 1977.
24.
SjolundBErikssonM. : Endorphins and analgesia produced by peripheral conditioning stimulation. In: BonicaJJLiebeskindJCAlbe-FessardD eds. Advances in pain research and therapy. New York: Raven Press, 1979, 3, pp 587–592.
25.
WatkinsLRCobelliDAFarisPAcetoMDMayerDJ. : Opiate vs non-opiate footshock-induced analgesia (FSIA): the body region shocked is a critical factor. Brain Res242:299–308, 1982.
26.
WilierJCDehenHCambierJ. : Stress-induced analgesia in human: endogenous opioids and naloxone-reversible depression of pain reflexes. Science212:689–691, 1981.
27.
Sternbach RA : Pain, a psychophysiological analysis. New York and London: Academic Press,1968, pp 185.
28.
Von Graffenried B, Adler R, Abt K, Nuesch E, Spiegel R. : The influence of anxiety and pain sensitivity on experimental pain in man. Pain4:253–263, 1978.
29.
MooreNEBerkSN. : Acupuncture for chronic shoulder pain: an experimantal study with attention to the role of placebo and hypnotic susceptibility. Ann Intern Med48:381–384, 1976.
KrogerWS. : Acupunctural analgesia: its explanation by conditioning theory, autogenic training and hypnosis. Amer J Psvchol130:855–860, 1973.
32.
MelzackRWallPD. : Pain mechanisms: a new theory. Science150:971–979, 1965.
33.
MayerDJPriceDD. : Central nervous system mechanisms of analgesia. Pain2:379–404, 1976.
34.
Le Bars D, Dickenson AH, Besson JM. : Diffuse Noxious inhibitory controls (DNIC). II. Lack of effect on non- convergent neurones, supra-spinal involvement and theoretical implications. Pain6:305–327, 1979.
35.
LevineJDGordonNC and FieldsHC. : The mechanisms of placebo analgesia. Lancet654–657, 1978.
36.
GoldsteinAHilgardERI. : Failure of opiate antagonist naloxone to modify hypnotic analgesia. Proc Acad Sci (Wash)72:2041–2043, 1975.
ErnstMLeeMH. : Sympathetic vasomotor changes induced by manual and electrical acupuncture of the Hoku point visualized by thermography. Pain21:25–33, 1985.
39.
EdwallLScottD. : Influence of changes on the excitability of the sensory unit in the tooth of the cat. Acta Phvsiol Scand82:555–556, 1971.
40.
SawynokJPinskyCLa Bella FS. : Mini-review on the specificity of naloxone as an-opiate antagonist. Life Sci25:1621–1632, 1979.
41.
LevineJDGordonNCFieldsHL. : Naloxone dose dependently produces analgesia and hyperalgesia in post-operative pain. Nature (lond)278:740–741, 1979.
42.
ChapmanCRBebedettiC. : Analgesia following transcutaneous electrical stimulation and its partial reversal by a narcotic antagonist. Life Sci21:1645–1648, 1977.
43.
ChengRSPomeranzB. : Electroacupuncture could be mediated by at least two pain-relief acupuncture analgesia in man by the narcotic antagonist naloxone. Brain Res121:368–372, 1977.
44.
SjolundBErikssonM. : The influence of naloxone on anlgesia produced by peripheral conditioning stimulation. Brain Res 173: 295–301, 1979.
45.
Le Bars D, Chitour D, Kraus E, Dickenson AH, Besson JM. : Effect of naloxone upon diffuse noxious inhibitory controls (DNIC) in the rat. Brain Res41:387–402, 1981.
