Sheng Li Xue Bao. 1990 Dec; 42(6): 523-33.

[Role of afferent C fibers in electroacupuncture of "zusanli" point in activating nucleus raphe magnus]

Liu XA, Jiang MC, Huang PB, Zou T.

Institute of Acupuncture and Moxibustion, China Academy of Traditional Chinese Medicine, Beijing.

The purpose of the present work is to study whether the analgesia of "Zusanli" EA was mainly produced by its noxious effect. The antidromic C waves on N. peroneus communis innervating the area of "Zusanli" point were recorded. When "Zusanli" point was stimulated by trains of stimuli, the amplitude of the antidromic C wave was obviously decreased due to collision with the orthodromic stimulation. It was suggested that EA of "Zusanli" could excite some C fibers. It was observed that when the stimulation intensity reached the threshold of C fiber, the NRM neurons were obviously activated, and when it reached or exceeded the intensity for producing the maximal C wave, the NRM neurons were highly activated. Therefore, EA analgesia is probably produced mainly by its noxious stimulus component, especially carried by C fibers, via a negative feedback mechanism in modulating pain.