【摘要】 电刺激或降低细胞外的镁离子浓度，会引起Ｎ－甲基－Ｄ－天门冬氨酸受体通道的开放，造成胞内外离子浓度失平衡．使用离子选择性微电极结合脑片技术，对电刺激和低镁溶液引起的大鼠内嗅皮层游离钙和钾离子浓度及电位的动态变化的规律进行了研究。实验结果表明，电刺激和低镁溶液引起的内嗅皮层游离钙和钾离子浓度的改变，在细胞层Ⅳ－Ⅴ（皮层表面下９００－１１００μｍ）变化最大。低镁溶液引起游离钙离子浓度下降，同时钾离子浓度呈双相变化，即先增加后减少。低镁溶液灌流内嗅皮层脑片数小时后，胞外钙离子浓度持续地停留在低浓度水平，而钾离子浓度受影响较小．更多还原

【Abstract】 In this study, dynamic changeS in [Ca2+]0,[K+]0 and field potential induced during electrical stimulatin and perfusion of low Mg2+ medium were wjth combined ion-selective microelectrodes in different layers of rat entorhinal cortex. Ih physiological solution, repetitive stimulatin (10s,20Hz,0.1ms)evoked reduction in[Ca2+]0, the in [K+]0 and change in field potential.All of them had the maxial change at layers Ⅳ- Ⅴ. In low Mg2+ medium. spontalleous epileptiform discharge,decrease in [Ca2+]0, and two phase changes(overshoot and undershoot)in [K+]0 were observed in all layers of the entorhinal cortex.The results indicated that changed in [Ca2+]0, [K+]0 and in field potential in the entorhinal cortex were maximal in layers Ⅳ-Ⅴ,Which receive input from other brain structures.Activation of NMDA receptor for several hours will damage the neuronal function of pumping out Ca2+,but has limited effect on the action of intaking K+ of the neuroglia.更多还原