[Effect of electro-acupuncture (EA) on response of cerebellar cortex to slow pain]

Experiments were performed on cats under chloralose anaesthesia and immobilized by Flaxedil. The right saphenous nerve was stimulated with single rectangular electric pulse of 30V and A-fibers were blocked selectively by the anodal current so as to elicic the C-fiber input only. The cerebellar cortical field potential evoked by C-fiber input (C-CEP) was recorded on the contralateral vermian VI lobule surface. C-CEP can be inhibited obviously by injecting the morphine (0.5 mg/kg) intravenously. It indicated that C-CEP had the close concern with the slow pain information and might be regarded as the index of the slow pain. The effects of the EA at the "Zusanli" point on C-CEP were observed. The results as following: 1. The amplitude of C-CEP decreased obviously after the EA at the ipsilateral "Zusanli" (strength: 10V, duration: 0.2 ms, frequency: 5 Hz). 2. From 5V-30V the more the strength of the EA was, the more the inhibitory efficiency was. 3. The inhibitory efficiency of the EA at the ipsilateral "Zusanli" point on C-CEP was stronger than at the contralateral, and the strongest at the bilateral.