钙离子介导NMDA受体与AMPA受体的相互抑制

目的观察NMDA受体与AMPA受体之间的相互抑制作用及其作用机制.方法采用全细胞膜片钳技术记录培养大鼠海马神经元谷氨酸受体电流.结果在培养大鼠海马神经元上记录到10^-4mol/L NMDA和10^-4mol/L AMPA分别诱导的内向阳离子电流,同时施加NMDA和AMPA所诱导的钙电流幅度明显小于分别施加两者之和;而诱导的钡电流则无此现象.结论NMDA受体与AMPA受体存在相互抑制作用,该抑制作用可能通过内流的Ca^2＋介导.

The cross- inhibition between NMDA receptor and AMPA receptor is mediated by Ca2+

Objective To investigate mechanism of the cross - inhibition between NMDA receptor and AMPA receptor. Methods Whole - cell patch - clamp was used to record the NMDA - and AMPA - induced whole - cell currents in acutely dissociated rat hippocampal neurons. Results It was verified that activation of NMDA receptor and AMPA receptor will lead to influx of sodium and calcium ions, which can modulate ionotropic glutamate receptor activity. In the present study, the authors also found that the whole - cell calcium current induced by both NMDA and AMPA together was significantly less than the predicted sum of the currents induced by NMDA and AMPA independently. However, when the calcium ions in the media were replaced with barium ions, the difference would become appreciable no more. Conclusion Calcium might mediate the cross - inhibition between NMDA receptor and AMPA receptor.