[Relation of capsaicin-sensitive neurones to the effect of electro-acupuncture analgesia].
In this experiment, the rats treated with capsaicin (50 mg/kg) s. c. on day 2 of liqe were used 12 weeks after injection. The levels of substance P(SP) in sciatic nerves and dorsal spinal cords were measured with radioimmunoassay to evaluate the extent of C-afferent fibers damaged by capsaicin. The results as follows: (1) the levels of SP in the sciatic nerve and the dorsal spinal cord are decreased by 69% and by 62% respectively, indicating the degeneration of the primary C-afferent fibers is very massive; (2) the average of basal tail-flick latency (immersing in 50 degrees C water) is prolonged 105% as compared with the control; (3) after electro-acupuncture, the average of tail-flick latency of the capsaicin treated rats is increased by 81%, while that of the vehicle treated rats increased by 54%. These data suggest that C-afferent fibers substantially mediate the transmission of noxious thermal stimuli, but is unnecessary for the transmission of acupuncture message to induce analgesia.
Institute of Acupuncture and Moxibustion, China Academy of Traditional Chinese Medicine, Beijing.
Z
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Lu
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Cao
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Dong
Y
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Deng
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T
Zhang
D015667:Acupuncture Analgesia; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D015671:Electroacupuncture; D008297:Male; D009412:Nerve Fibers / Q000502:physiology; D009474:Neurons / Q000502:physiology; D009619:Nociceptors / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains; D012684:Sensory Thresholds / Q000187:drug effects; D013373:Substance P / Q000378:metabolism
D013373:Substance P; D002211:Capsaicin