电生理学特性得到确定的大鼠脊髓背根神经节细胞内谷氨酸和P物质的共存  

CO-EXISTENCE OF GLUTAMATE AND SUBSTANCE P IN ELECTROPHYSIOLOGGICALLY IDENTIFIED DORSAL ROOT GANGLION N'EURONS OF RATS

作　　者：杨鲲[1] 王过渡[2] 李云庆[1] 施际武[1] 赵志奇[2] 

机构地区：[1]第四军医大学基础部解剖学教研室,西安710032 [2]中国科学院上海脑研究所,上海200031

出　　处：《生理学报》1998年第4期453-459,共7页Acta Physiologica Sinica

基　　金：国家杰出青年科学基金!39625011

摘　　要：在离体灌流带脊髓和坐骨神经的标本上，对脊髓背根神经节（DRG）细胞的电生理学特性、对P物质（SP）受体激动剂的反应及谷氨酸（Glu）／SP共存的特点进行了研究。（1）对135个细胞进行了细胞内记录，并依纤维传导速度将其分为Aα／β（＞12m／s）和C（＜1．3m／s）两大类；它们的动作电位的快速后超极化（fAHP）有明显区别，C类的fAHP幅度小、时程长，Aα／β类的fAHP幅度大、时程短；（2）SP受体激动剂Sar－SP（10－6mol／L）诱导42％（5／12）的Aα／β细胞和80％（8／10）的C细胞发生去极化反应；（3）最后向给予SP受体激动剂的22个细胞内电泳biocytin，固定、切片后进行磷酸激活的谷氨酰胺酶（PAG）和SP免疫荧光组织化学染色并同时显示biocytin，观察到biocytin标记并呈PAG样和SP样阳性的三标细胞在Aα／β类为25％（3／12），C类为80％（8／10），两者差异显著（P＜0.05）。结果提示DRG中Aα／β细胞与C细胞的化学解剖和电生理特性不同，SP可能通过作用于节细胞上的自身受体易化冲动的发放。Electrophysiological properties, reaction to sustance P (SP) receptor agonist, and co-existence of glutamate (Glu) and SP in neurons of the spinal dorsal root ganglion (DRG) of the rat were investigated in vitro.The main results were: (1) According to the fiber conduction velocity, totally 135 intracellularly recorded DRG neurons were divided into Aα/β type(> 12m/s) and C type (<1.3 m/s). There were remarkable differences between the fast afterhyperpolarization (fAHP) of action potential between the two types:fAHP of C type neurons had smaller amplititude and longer duration, whereas the fAHP of Aα/β type neurons had larger amplititude and: shorter duration. (2) Among 22 DRG neurons of which overshoots of action. protential appeared, specific SP receptor agonist Sar-SP induced depolorization in 42% (5/12) of the Aα/β type neurons and 80% (8/10)of the C type neurons. (3) Biocytin was intracellularly injected into the 22 Sar-SP administrated DRG neurons. After fixation and section, employing the inmmunofluorescent histochemical multi-staining technique for phosphate-activated glutaminase (PAG, aspecific marker for glutamatergic neurons), SP and biocytin, 25% (3/12) of the Aα/βtype neurons and 80% (8/10) of the C type neurons showed both PAG and SP-like immunoreactivities.There was a great difference between the percentages of the PAG/SP co-existing Aα/β type neurons and C type neurons (P < 0.05 ). The present results indicated that there were some differences in chemicoanatomical and electrophysiological properties between Aα/β type and C type neurons, and SP might facilitate the discharge of DRG neurons through activating SP autoreceptors on their membrane.

关 键 词：背根神经节 细胞内标记 递质共存 大鼠 电生理学 

分 类 号：Q424[生物学—神经生物学]