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机械分离的果蝇幼虫中枢神经元全细胞钾电流的特性

徐太湘, 吕辉, 王强, 伍龙军, 刘进, 周专, 徐天乐

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.安徽,合肥 230027；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；中科院上海神经科学研究所.上海 200031

摘要

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,而且它具有与其它四种电流不同的衰减特性。

关键词： 果蝇; 机械分离; Ⅱ型神经元; 钾电流

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

Xu Taixiang, Lu Hui, Wang Qiang, Wu Longjun, Liu Jin, Zhou Zhuan, Xu Tianle

Department of Neurobiology & Biophysics, School of Life Sciences,University of Science and Technology of China.Hefei 230027,Anhui；China；Neuroscence Institute of Shanghai, Chinese Academy of Sciences.Shanghai 200031

Abstract

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 E current 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.

Key words: Drosophila;Mechanical dissociation;Type II neuron;K~(+)current

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引用本文：

徐太湘, 吕辉, 王强, 伍龙军, 刘进, 周专, 徐天乐. 机械分离的果蝇幼虫中枢神经元全细胞钾电流的特性[J]. 生理学报 2002; 54 (5): .

Xu Taixiang, Lu Hui, Wang Qiang, Wu Longjun, Liu Jin, Zhou Zhuan, Xu Tianle. Properties of whole-cell potassium currents in mechanically dissociated Drosophila larval central neurons. Acta Physiol Sin 2002; 54 (5): (in Chinese with English abstract).