大鼠三叉神经节不同直径神经元ATP-激活电流的特征  

ELECTROPHYSIOLOGICAL CHARACTERISTIC OF ATP-ACTIVATED CURRENTS OF TRIGEMINAL GANGLION NEURONS WITH DIFFERENT DIAMETER IN RAT

作　　者：张玉芹[1] 罗加烈[2] 聂辉[1] 朱凡[1] 李之望[2] 

机构地区：[1]武汉科技大学医学院生理学教研室,湖北武汉430080 [2]华中科技大学同济医学院神经生物学系,湖北武汉430030

出　　处：《中国应用生理学杂志》2007年第3期319-323,共5页Chinese Journal of Applied Physiology

基　　金：湖北省自然科学基金资助(2004ABA152)

摘　　要：目的：探讨大鼠三叉神经节不同直径神经元ATP-激活电流的特征。方法：应用全细胞膜片钳技术进行实验。结果：①92.3%（60/65）的细胞对ATP敏感,有反应的细胞可记录到三种型式的ATP-激活电流：快速激活快速失活型（Fast type,F型）、快速激活缓慢失活型（Intermediate type,I型）和缓慢激活缓慢失活型（Slowtype,S型）。三种电流均具有浓度依赖性。②小直径的细胞多表现为F型特征,大直径的细胞多表现为S型特征,而中等大小的细胞多表现为I型特征。③动力学特征：三种类型的ATP激活电流上升相从10%到90%的时间：F型：（33.6±4.5）ms;Ⅰ型：（62.2±9.9）ms;S型：（302.1±62）ms。去敏感相从10%到90%的时间：F型：（399.4±58.2）ms;S型：〉500ms。④I-V曲线：三种电流均表现为内向整流的特性,而且翻转电位均为0~5mV。⑤量-效关系：Ⅰ型的量-效曲线居中间,F型的下移,S型的上移,三种类型电流量-效曲线的EC50非常接近。结论：三种型式的ATP-激活电流可能是由不同亚单位组合的P2X受体各亚型所介导,这些亚型分布于不同大小的三叉神经节神经元,从而传导不同的信息。Aim：To explore the characteristic of ATP-activated current in trigeminal ganglion（TG）neurons of rat.Methods：Whole-cell patch-clamp was performed.Results：①The majority（92.1%）of TG neurons responded to ATP applied externally with inward currents.We recorded three distinct ATP-activated currents：fast,slow and intermediate,which were concentration-dependent.②In general,the fast ATP-activated currents were distributed mainly in small-diameter TG neurons,the slow ATP-activated currents were distributed mainly in large-diameter TG neurons,and the intermediate ATP-activated currents were distributed mainly in intermediate-diameter TG neurons.③The time course of rising phase from 10% to 90% of the three distinct ATP-activated currents were as follows：fast：（33.6±4.5）ms;intermediate：（62.2±9.9）ms;slow：（302.1±62.0）ms,and that of desensitizing phase were（399.4±58.2）ms（fast）,and〉500 ms（slow）respectively.④From the current-voltage relationship curves,it can be seen that the reversal potential values of the three distinct ATP-activated currents were the same,all being 0-5mV.And they all were characterized by inward rectification.⑤The dose-response curve for fast ATP-activated current shifted downwards as compared with the intermediate ATP-activated current,and that for the slow ATP-activated current shifted upwards.Conclusion：The EC50s of the three curves tended to be identical.The results suggested that three kinds of distinct ATP-activated currents could be mediated by various subtypes of P2X receptors assembled by different subunits,and the subtypes existed in TG neurons of different diameters and transmit different information.

关 键 词：ATP-激活电流 离子型ATP受体 全细胞膜片钳 三叉神经节 大鼠 

分 类 号：R338.3[医药卫生—人体生理学]