机械分离的果蝇幼虫中枢神经元全细胞钾电流的特性  

Properties of whole-cell potassium currents in mechanically dissociated Drosophila larval central neurons

作　　者：徐太湘[1] 吕辉[1] 王强[1] 伍龙军[1] 刘进[2] 周专[3] 徐天乐[1] 

机构地区：[1]中国科学技术大学生命科学学院神经生物学和生物物理学系 [2]中国协和医科大学阜外医院麻醉及体外循环实验室,北京100037 [3]中国科学院上海神经科学研究所,上海200031

出　　处：《生理学报》2002年第5期411-416,共6页Acta Physiologica Sinica

基　　金：ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina (No30125015);agrantforOutstandingYoungResearchersfromtheMinistryofEducationofChinaandNationalBasicResearchProgram(G19990 5 40 0 0 )toT L Xu .

摘　　要：培养的果蝇胚胎及幼虫中枢神经元已被广泛用于细胞膜离子通道、突触传递和胞内信使调节等电生理学研究。在本实验中 ,利用机械震荡分离方法获得了大量的果蝇幼虫中枢神经元 ,其中大部分为Ⅱ型神经元。运用膜片钳技术 ,鉴定了Ⅱ型神经元上五种具有不同动力学特性的全细胞钾电流。其中E型电流表型表现出与其它四种电流完全不同的“钟形”激活特性。进一步的研究还表明该类型电流具有明显的钙依赖性 。By electrophysiological methods, cultured Drosophila embryonic and larval central neurons have been widely used to study ion channels, neurotransmitter release and intracellular message regulation. Voltage activated K + channels play a crucial role in repolarizing the membrane following action potentials, stabilizing membrane potentials and shaping firing patterns of cells. In this study, a mechanical vibration isolation system was used to produce a sufficient number of acutely dissociated larval central neurons, of which the majority were type Ⅱ neurons (2～5 μm in diameter). Using patch clamp technique, the whole cell K + currents in type Ⅱ neurons were characterized by containing a transient 4 AP sensitive current ( I A) and a more slowly inactivating, TEA sensitive component ( I K). According to their kinetic properties, five types of whole cell K + currents were identified. Type A current exhibited primarily fast transient K + currents that activated and inactivated rapidly. The majority of the neurons, however, slowly inactivated K + currents with variable inactivation time course (type B current). Type C current, being present in a small number of the cells, was mainly composed of noninactivating components. Some of the neurons expressed both transient and slow inactivating components, but the slowly inactivating components could reach more than 50% of the peak current (type D current). Type E current showed distinct voltage dependent activation properties, characterized by its 'bell shaped' activation curve. Type Ecurrent was inhibited by application of Ca 2+ free solution or 0 1 mmol/L Cd 2+ . Moreover, this novel current ran down much more rapidly than other types. These results indicate that different K + channels, which have different kinetic and pharmacological properties, underlie the whole cell K + currents in type Ⅱ neurons of Drosophila larval central nervous system.

关 键 词：机械分离 果蝇幼虫 中枢神经元 全细胞钾电流 Ⅱ型神经元 

分 类 号：Q424[生物学—神经生物学]