尾核内的多巴胺(DA)可能具有对抗电针镇痛的效应。尾核内微量注射胆硷能受体阻断剂——东莨菪硷可不同程度地阻断电针的镇痛作用。尾核内来自黑质致密部的多巴胺能神经末梢与尾核内的胆硷能中间神经元发生联系。那么

尾核多Fhe dopaminergic neuro-transmitter in caudate nuclei probably has an opposite effect on electroacupuncture analgesia.The increased pain threshold brought about by electroacupuncture was reduced when a cholinergic blockadescopolamine was injected in minute amount into both caudate nuclei. The present study invetigated the effect of intracaudate injection of a cholinergic agent-pilocarpine on antielectroacupuncture analgesia induced by intracaudate injection of dopamine.Experiment were performed on rabbits with chronically implanted canulae for injection in bilateral caudate nuclei.The pain threshold was determined by heat flicks in response to radiant heat on the tip of the nose.The position of electroacupuncture was“Zusanli”point.All the experimented rabbit's brains were verified histologically and the cases which canulae were inserted exactly into caudate nuclei were included in the statistic analysic. When pilocarpine was injected into caudate nuclei

the reduced pain thre- shold by intracaudate injection of dopamine was reversed.The results suggest that excitation of cholinergic neurons in caudate nuclei might strength the electroacupuncture analgesia.The dopaminergic antielectroacupuncture analgesic effect might be carried out by the way of cholinergic neuron in caudate nucl- ei.