【摘要】 【目的】探讨多巴胺(DA)对前额叶皮层锥体神经元谷氨酸/N-甲基-D-天冬氨酸(NMDA)受体的调节作用。【方法】使用细胞贴附式膜片钳技术进行单通道记录,观察不同浓度DA对急性分离的前额叶皮层锥体神经元NMDA受体通道电流的影响。【结果】结果表明:当DA浓度为0逐渐升高到60!mol/L时,NMDA受体通道的电流幅度由(2.78+0.68)pA升高到(5.42+1.26)pA;短开放时间常数变化不明显,但长开放时间常数由(13.59+1.26)ms升高到(36.19+1.17)ms;长关闭时间常数由(19.73+1.46)ms降低到(2.67+0.75)ms;通道开放概率由0.25+0.09升高到0.56+0.25;当DA浓度继续由60!mol/L升高到100!mol/L时,NMDA受体通道的电流幅度回落到(3.56+0.79)pA,长开放时间常数回落到(14.40+1.37)ms;长关闭时间常数恢复为(17.74+1.79)ms,与对照组比较无显著性变化;通道开放概率由0.56+0.25降低到0.17+0.08。【结论】DA可以影响前额叶皮层锥体神经元NMDA受体通道的活动,而且具有浓度依赖性,低浓度有明显促进作用,高浓度则促进作用减弱,甚至有抑制作用。更多还原

【Abstract】 【Objective】To investigate the modulatory effects of dopamine (DA) on N-methyl-D-aspartate (NMDA)receptor channels of the pyramidal neurons in prefrontal cortex in rat. 【Methods】 Cell-attached configuration of patch clamp was used to record single-channel currents of NMDA receptors. The effect of DA in different concentration on the electricity of NMDA receptor channel was observed【.Results】 When the concentrations of DA increased gradually from 0 to 60 !mol/L, the amplitude of NMDA receptor channel currents was increased from(2.78+0.68) pA to (5.42+1.26) pA; the short open-time-constant did not change significantly, the long open-time-constant increased from (13.59+1.26) ms to (36.19+1.17) ms, and open probability of inward currents of NMDAreceptor channels increased from 0.25+0.09 to 0.56+0.25; and the long closing-time-constant decreased from (9.73+1.46) ms to (2.67+0.75) ms. However, when the concentrations of DA increased from 60 μmol/L to 100 !mol/L, theamplitude of NMDA receptor channel currents was decreased to (3.56+0.79) pA, long open-time-constant decreasedto (14.40+1.37) ms, long closing-time-constant restored to (17.74+1.79) ms, and the open probability of NMDAreceptor-channel decreased to 0.17+0.08.【Conclusion】DA could affect the activities of NMDA receptor channels,but there was relationship of reverted U shape and the increases in concentrations of dopamine. At low concentra-tions, DA enhanced the activation of NMDA receptor channels, but inhibited the activation of NMDA receptor chan-nels at high concentrations.更多还原