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大脑皮层神经元NMDA受体的单通道特性

高天明, 邹飞, 陈培熹

中山医科大学生理学教研室. 广东, 广州 510089

摘要

用膜片箝技术对机械分离培养的大鼠大脑皮层神经元胞体上的NMDA受体的单通道特性进行了研究, 实验用细胞贴附和内面向外两种形式记录单离子通道的活动。电极液内含有NMDA或L-门冬氨酸时, 在皮层神经元上常见电导为35ps的离子通道。通道对Na~(+)、K~(+)非选择性通透, 对Cl~(-)不通透, 其平均开放时间和开放概率随超极化程度增 大而降低。开放、关闭时间及burst时程的分布直方图均需双指数拟合。Mg~(2+)以电压和浓度依赖性的方式减少通道开放时间, APV能阻断通道活动, 温度降低通道开放时间延 长及电流幅度减小。结果表明大脑皮层神经元上的NMDA受体通道活动自身具有电压依赖性, 因此提示NMDA受体通道的正常功能活动可能依赖于某些细胞内调控过程的存在。图7参21

关键词： 膜片箝; NMDA受体通道; 大脑皮层神经元

Single channel properties of NMDA receptors in cortical neurons

Gao Tianming, Zou Fei, Chen Peixi

Department of Physiology, Sun Yat--Sen University of Medical Sciences. Guangzhou 510089, Guangdong

Abstract

The cell--attached and inside--out configurations of the patch-clamp techniques were used to investigate single channel properties of NMDA receptors in cultured intat neurons mechanically isolated from rat cereberal cortex. Recordings were made in Mg~(2+)--free solutions. A channel, with a conductance of 35 pS was studied in detail with either NMDA or L--aspartate in the patch pipette. NMDA channels were permeableto Na~(2+)and K~(+), but not to Cl~(-), the mean open times and open probabilities of these channels were decreased with increasing hyperpolarization. distributions for the open times, closed times and burst durations repuired two--component fits. Channel openings were supressed by APV. When Mg~(2+)was inclued in the pipette, the mean open tmes were significantly diminished in a concentration- and voltage--dependent manner. Decreasing the bath temperature prolonged channel open times and decreased current amplitudes. The results indicate that there is an intrinsic voltage dependence of NMDA channel kinetics in the intact neurons, suggesting that the normal function of the NMDA channel may be dependent on some intracellular biochemical process

Key words: Patch clamp;NMDA receptor channels;Conical neurons

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引用本文：

高天明, 邹飞, 陈培熹. 大脑皮层神经元NMDA受体的单通道特性[J]. 生理学报 1995; 47 (2): .

Gao Tianming, Zou Fei, Chen Peixi. Single channel properties of NMDA receptors in cortical neurons. Acta Physiol Sin 1995; 47 (2): (in Chinese with English abstract).