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新生大鼠大脑皮层神经元胞体ATP激活的离子通道及其特性

任俊, 陈助华, 陈培熹

中山医科大学生理学教研室，广州510089)

摘要

用膜片籍技术的细胞贴附式和内面向外式，在机械分离的新生SD大鼠的大脑皮层神经元上，记录到ATP激活的离子通道。此通道的电导为32 pS，对Na+, K+和cs+无选择性通透，而对C1一不通透。通道开放时间分布直方图多数需用双指数拟合，少数可用单指数拟合;通道关闭时间分布直方图均需用双指数拟合。通道的平均开放时间和开放概率均不依赖于膜电位，但通道的开放概率随着激动剂ATP浓度的增加而增大。当电极内液无ATP时，无通道电流。六烃季胺和美加明不能阻断此通道。上述结果表明，新生大鼠的大脑皮层神经元胞体可能存在ATP激活的离子通道。

关键词： :ATP; 离子通道; 膜片籍; 大脑皮层神经元

ATP-ACTIVATED SINGLE ION CHANNEL AND ITS PROPERTIES IN CEREBRAL CORTICAL NEURONS OF NEONATAL RAT

REN JUN, CHEN ZHU-HUA , CHEN PEI-XI

(Department of Physiology, Sun Yat-Sen University of Medical Sciences, Csuangzhou 510089)

Abstract

In the present study，single channel currents were recorded from single neurons dissociated from the cerebral cortex of neonatal SD rat by the cell-attached and inside- out modes of patch clamp technique. ATP-activated channels with a conductance of 32 pS were often recorded and permeable to Na+，K+ and Cs+，but not to Cl-. Most of open time distribution histograms were fitted by two exponential components and few by one，whereas closed time distribution histograms were fitted by two exponential components. Both mean open time and open probability were independent of membrane potential，but the latter increased with increasing ATP concentration. The channel activity
was recorded only in the presence of pipette solution containing ATP，and its conductance and open probability were not affected by ACh N-receptor antagonist hexamethonium and mecamylamine. It is suggested that ATP-activated ion channels probably exist in the cerebral cortical neurons of neonatal rat.

Key words: :ATP;Ion channel;patch clamp;cerebral cortical neurons

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引用本文：

任俊, 陈助华, 陈培熹. 新生大鼠大脑皮层神经元胞体ATP激活的离子通道及其特性[J]. 生理学报 1996; 48 (3): .

REN JUN, CHEN ZHU-HUA , CHEN PEI-XI. ATP-ACTIVATED SINGLE ION CHANNEL AND ITS PROPERTIES IN CEREBRAL CORTICAL NEURONS OF NEONATAL RAT . Acta Physiol Sin 1996; 48 (3): (in Chinese with English abstract).