电针对内脏大神经C类纤维传入诱发体感皮层电反应的影响

THE EFFECT OF ELECTRO-ACUPUNCTURE OF “NEIGUAN”ACUPOINT ON CORTICAL POTENTIAL EVOKED BY STIMULATING C-FIBERS OF SPLANCHNIC NERVE

我们曾报道,电针内关穴可抑制内脏大神经引起的大脑皮层诱发电位和大脑皮层后乙状回的内脏痛放电。由于腹腔内脏痛信息主要由内脏大神经C类纤维传导,因此,C类纤维引起的皮层诱发电位更能准确地反映内脏痛。本文拟用内脏大神经C类纤维传入引起的皮层诱发电位(C-CEP)作为内脏痛指标,观察电针内关穴及镇痛剂对内脏痛反应的影响。

In this paper the averaged cortical evoked potential (C-CEP) induced by stimulating the C-fibers of the splanchnic nerve was used as an index of visceral pain to further study the effects of acupuncture and morphine on it. Experiments were carried out on 35 cats anesthetized with chloralose and immobilized with flaxedil. The splanchnic nerve was stimulated with electric pulses of varied strength and blocked by a galvanic current so as to cause A- or C-fibers input selectively. The cortical evoked potential was recorded on the contralateral postsigmoid gyrus and averaged by TQ- 19 Medical Data Processor. The compound action potential of splanchnic nerve was monitored. 'Neiguan' acupoint was stimulated with electric pulses (0.1ms, 4v and 5Hz). The results were as follows: 1) when 'Neiguan' acupoint was excited with the electric pulses, C-CEP and the late component of A-CEP which was evoked by stimulating A-fibers of splanchnic nerve were obviously reduced in amplitudes. It was suggested that electro-acupuncture (EA) of 'Neiguan' acupoint could inhibit visceral pain (the slow and fast pain). 2. After intraveaous injection of morphine, the amplitudes of C-CEP and the late component of A-CEP were depressed significantly, indicating that C-CEP might reflect the visceral slow pain and the late component of A-CEP reflect the fast pain. 3. Naloxone could block partially the inhibitory effect of EA of 'Neiguan'acupoint on C-CEP, suggesting that the inhibition of EA might be associated with the release of endogenous opiate like substances.