Am J Chin Med. 1981 Summer; 9(2): 164-70.

Role of the subsequently activated receptors in electro-acupuncture of the rat.

Kawakita K, Funakoshi M.

Role of the subsequently excited receptors elicited by tetanic muscular contraction in electro-acupuncture analgesia was examined. Conditioning stimulation of the nerve (CPN) as well as electro-acupuncture induced a significant delay of the tail flick latencies of the rat with weak intensity of stimulus (1.0-1.5 x DFT), and this effect was abolished after section of the nerve at a point distal to the stimulating electrode. Electrophysiological data indicate that a small amplitude of the A large fiber group's potential was recorded with the intensity range of 1.0-1.5 x DFT. These facts suggest that the analgesic effect induced by weak stimulation is not the result of direct excitation of afferent fibers but the result of subsequent activation of receptors provoked by tetanic muscular contraction. The possible receptors are proposed and their participation in acupuncture analgesia also discussed. CPn = the common peroneal nerve; DFT = dorsal flexion threshold (1.0 x DFT = 1.15 x Ta).