锌离子对急性分离的大鼠骶髓后连合核神经元GABAA受体介导电流的抑制作用

采用制霉菌素穿孔膜片箝技术,研究了锌离子(Zn2+)对急性分离的大鼠骶髓后连合核神经元GABAA受体介导电流的作用.结果表明:(1)在箝制电压为-40mV时,GABA可通过GABAA受体介导产生内向电流;(2)此电流可被Zn2+呈非电压依赖性可逆地阻断;(3)在Zn2+存在的情况下,GABA的浓度-效应曲线平行右移.上述结果提示,Zn2+可能通过变构调控机制对GABAA介导的反应产生抑制作用.

Zn2+ DEPRESSES GABAA RECEPTOR MEDIATED RESPONSES IN ACUTELY DISSOCIATED SACRAL DORSAL COMMISSURAL NEURONS

The effects of Zn2 + on GABAA-receptor mediated responses in acutely isolated rat sacral dorsal commissural nucleus (SDCN) were studied using nystatin-perforated whole cell recording techniques.The results demonstrated that ( 1 ) GABA induced inward currents through activation of GABAA-receptor at a holding potential of -40 mV; (2) GABAA-receptor mediated responses were suppressed by Zn2 + in a reversible and voltage-independent manner; and (3) in the presence of Zn2 + , the concentration-response curve of GABA-induced responses was shifted to the right in a parallel manner. The results suggest that Zn2 +allosterically depresses GABAA-receptor mediated currents.