P物质对胃肠感觉传入功能的影响

Effect of substance P on sensation afferent function of gastrointestinal tract

目的:研究P物质对胃肠感觉传入冲动的影响及其机制。方法:将40只SD大鼠分成5组:正常对照组(NS)、SP小剂量组(75ng/kg)、中剂量组(150ng/kg)、大剂量组(300ng/kg)及spantideⅡ+SP组。应用电生理方法,观察各组注射前后膈下迷走神经传入自发放电以及扩胃诱发放电的变化情况。结果:SP中、大剂量组膈下迷走神经传入自发放电均增强(P<0.05),大剂量组扩胃诱发传入放电减少(P<0.05);先给予spantideⅡ后再给予SP,SP对膈下迷走神经传入自发放电和胃扩张诱发传入放电的效应均消失。结论:静脉注射SP对膈下迷走神经传入自发放电具有兴奋作用,并表现为剂量依赖性;SP对扩胃诱发传入放电具有抑制作用;这些效应可能均通过神经激呔-1受体NK1受体介导产生。

Objective：To study the effect of substance P on sensation afferent of gastrointestinal tract and the corresponding mechanism. Methods：Forty SD rats were divided into 5 groups： control group, low dosage SP group （75 ng/kg）, middle dosage SP group（150ng/kg）, high dosage SP group （300 ng/kg） and spantideII ＋ SP group. The electrophysiological method was used to record the change of spontaneous and gastric distention-induced afferent discharge of subdiaphragmatic vagus nerve in each group. Results：Intravenous SP （150 ng/kg,300 ng/kg） caused significantly increasing effect on the spontaneous afferent discharge （P〈0.05）,high dosage SP caused decreasing effect on the gastric distention-induced afferent discharge of subdiaphragmatic vagus nerve （P〈0.05）. Spantide Ⅱ＋ SP significantly inhibited the effect of SP mentioned above. Conclusion：SP elicits excitatory effect on the spontaneous afferent discharge, and the effect may show dose dependent on SP. SP elicits inhibitory effect on gastric-distention induced discharge of subdiaphragmatic vagus nerve. The action of exogenous SP afferent discharge of subdiaphragmatic vagus nerve is possibly mediated by NK1 receptor distributed in the stomach.