去甲肾上腺素、甘氨酸、γ-氨基丁酸和L-谷氨酸在大鼠脊髓场电位神经化学起源中的作用

The Role of NE, Gly, GABA and L-Glu in the Neurochemical Origin of Spinal Fielb Potentials in the Rats

于麻醉或清醒、麻痹大鼠腰膨大处观察了在记录电极局部脊髓背表面施加和向脊髓背角微电泳去甲肾上腺素NE)甘氨酸(Gly)、γ-氨基丁酸(GABA)和L-谷氨酸(L-Glu)时节段性脊髓场电位(SP)与下行性脊髓场电位(DP)的变化,结果表明,局部给药时,NE使SP与DP的N,P波波幅均明显降低;Gly、GABA和L-Glu明显降低SP与DP的N波波幅,但明显增大P的幅度。微电泳时,NE对N、P波呈减弱和增强两种效应;Gly明显削弱SP与DP的N、P渡;GABA减弱N波同时加强P披;L-Glu使N、P波幅度均显著增大,提示NE,Gly、GABA和L-Glu可能通过影响中间神经元及(或)初级传入末稍的活动,参与SP特别是DP的N,P波的形成。

NE, Gly, GABA and L-Glu were topically applied to the dorsal surface of lumbar spinal cord or iontophoretically injected into the spinal dorsal horn to observe their effects on segmental (SP) ant descending (DP) spinal field potentials on anesthetized (or conscious) and immobilized rats. In the group of topical application(TA), both waves N and P of SP and DP were seen to be reduced markedly in their amplitudes following TA of NE. A significant decrease in wave N's magnitude and a remarkable increase in wave P's size in both SP and DP were shown during TA of Gly, GABA and L-Glu. In the group of iontophoretical injection(II), either reduced or enhanced effect was shown during II of NE; both waves N and P of SP and DP were reduced in the course of II of Gly; a decreace in wave N's amplitude and an increase in wave P's size in both SP and DP were seen following II of GABA; the magnitude of waver N and P in both SP and DP was markedly increased when L-Glu was injected. The results indicate that the NE, Gly, GABA and L-Glu may be involved in the generation of waves N and P of SP and DP in particular, influencing the activity of spinal interneurons and/or intraspinal terminanls of primary afferents.