血管紧张素Ⅱ对脊髓背角神经元伤害性诱发放电及对电针抑制作用的影响

Effects of Angiotensin Ⅱ on the Nociceptive Discharges of Spinal Dorsal Horn Neurons in Rats

以玻璃微电极记录脊髓腰段(L_(2～3))背角神经元电活动,观察血管紧张素Ⅱ(A Ⅱ)对其诱发放电的影响及其与电针效应的关系。结果表明:(1)50～500 ng/20 μl A Ⅱ脊髓背表面微量注射对脊髓背角神经元伤害性诱发放电可产生抑制性效应(25/35)或易化效应(10/35);(2)2 μg/20 μl AⅡ对背角神经元伤害性诱发放电为易化效应(5/5);(3)250 ng/20 μA Ⅱ能增强电针“足三里”及“三阴交”穴对背角神经元伤害性诱发放电的抑制作用(8/9),两者呈协同作用。结果提示:在脊髓水平,一定剂量的 A Ⅱ呈镇痛作用,而较大剂量则呈相反效应;一定剂量的 AⅡ可影响电针的效应。

Experiments were performen on 53 rats.The nociceptive discharges of spinal dorsal horn neurons were extracellularly recorded bY glass microelectrodes and was tested for the effects of angiotensin Ⅱ (AⅡ)on the nociceptive discharges of spinal dorsal horn neurons and AⅡ on the inhibitory effects of electro,acupuncture(EA).The results showed as follows:(a)The nociceptive discharges of spinal horn neurons were modulated by inhibitory(25/35)or facilitory(10/35)effects with AⅡ(50～ 500 ng/20μl)applied to the surface of spinal dorsal horn cord(L_(2～)(b)The facilitory effects (5/5)were observed with AⅡ(2μg/20μl)applied to the surface of spinal dorsal horn cord;(c) The inhibitory effects with EA(20 Hz,2～4 V,5 min)could be increased with AⅡ(250 ng/20 μl, 8/9).Therefore,AⅡ may modulate the nociceptive evoked discharges of spinal dorsal horn neurons and influence the effects of EA,and differnt effects can be produced when diffrent dosage of AⅡ is applied to the surface of spinal dorsal horn cord.