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刺激大脑皮层体感Ⅰ区和大脑脚对大鼠脊髓背角神经元伤害感受性反应的影响

袁斌, 王歌昕, 庞天赐, 刘新领

西安医科大学神经生理研究室. 西安 710061

摘要

在大鼠用玻璃微电极细胞外记录的方法,观察了刺激皮层体感Ⅰ区(SI区)和大脑脚(CP)对皮肤强电刺激诱发的脊髓背角广动力范围(WDR)神经元长潜伏期反应(C-反应)的影响。结果表明刺激SI区对背角WDR神经元C-反应的影响以抑制为主,刺激CP的作用与刺激SI区的作用相似,但刺激CP更为有效。抑制作用的持续时间在不同神经元差别很大,短者在刺激停止后仅持续400ms,长者可达10min以上。静注纳洛酮对抑制作用无明显影响,静注二甲麦角新碱在部分神经元可使抑制作用明显减弱或完全消失,提示5-HT部分参与皮层下行抑制作用的实现,而内鸦片肽则否。

关键词： 大脑皮层躯体感觉区; 大脑脚; 下行调控; 脊髓背角; 伤害感受性神经元

Effects of stimulation of SI cortex and cerebral peduncle on the nociceptive responses of spinal dorsal horn neurons in the rat

Yuan Bin, Wang Gexin, Pang Tianci, Liu Xinling

Research Laboratory of Neurophysiology, Xian Medical University. Xian 710061, China

Abstract

Single spinal dorsal horn neurons were recorded extracellularly with glass micropipettes，and the effect of stimulation of SI cortex or cerebral 'peduncle (CP) was observed on the long latency discharges (C-fiber evoked response) of the wide dynamic range (WDR)neurons induced by intense electrical skin stimulation. Inhibition was the predominant effect of SI cortex stimulation on the C-fiber evoked responses of WDR neurons. The effect of CP stimulation was similar to that of SI cortex stimulation，except that the former was much more effective than the latter. The inhibition lasted a period of time. varying from 400 ms to more than 10 min after CP stimulation in different neurons. Systemic naloxone had no significant effect on the inhibition produced by CP stimulation. Systemic methysergide reduced or eliminated the inhibition in a part of the neurons tested，suggesting that 5-HT，but not opioid peptides，is involved partially in mediation of the descending inhibitory effect originating from the cortex.

Key words: Somatosensory cortex;Cerebral peduncle;Descending control;Spinal dorsal horn;Nociceptive neurons

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引用本文：

袁斌, 王歌昕, 庞天赐, 刘新领. 刺激大脑皮层体感Ⅰ区和大脑脚对大鼠脊髓背角神经元伤害感受性反应的影响[J]. 生理学报 1993; 45 (1): .

Yuan Bin, Wang Gexin, Pang Tianci, Liu Xinling. Effects of stimulation of SI cortex and cerebral peduncle on the nociceptive responses of spinal dorsal horn neurons in the rat. Acta Physiol Sin 1993; 45 (1): (in Chinese with English abstract).