N-甲基-D-天冬氨酸对神经细胞内游离钙水平的影响

EFFECTS OF N-METHYL-D-ASPARTATE ON INTRACELLULAR FREE CALCIUM ION CONCENTRATION IN NEURONS

目的:探讨N-甲基-D-天冬氨酸(NMDA)对神经细胞内游离钙离子浓度的影响,并初步探讨其作用机制。方法:采用钙离子荧光指示剂Fura-2/AM和双波长检测技术测定细胞内游离钙的浓度。结果:1×10-8～1×10-4mol/LNMDA可使大鼠神经细胞内游离钙[Ca2+]i水平显著升高(P<0.05),且呈剂量和时间依赖关系。结论:NMDA升高神经细胞内[Ca2+]i的作用与胞外Ca2+大量内流和胞内Ca2+储池释放有关,且以胞外Ca2+内流为主。胞外Ca2+内流不仅与NMDA受体门控Ca2+通道和电压门控Ca2+通道有关,还与电压依赖性Na+通道有关。

Objective： To investigate the effects of N-methyl-D-aspartate（NMDA） on intracellular free calcium[Ca^2＋]i dissociated neurons in newborn rats and its possible mechanism. Methods： Calcium fluorescent indicator fura-2/AM was used. Results： NMDA could increase the level of intracellular free Ca^2＋ of corticocerebral neurons significantly（P〈0.05）, and the concentrations of [Ca^2＋]i response to NMDA were dose-time dependent. Conclusion.- NMDA-induced increases in [Ca^2＋]i were associated with the influx of Ca^2＋ from outside of cells and release of stored Ca^2＋, mainly with the influx of Ca^2＋ from outside of cells. Furthermore, the influx Ca^2＋ from outside of the cells was related not only to NMDA receptor gated Ca^2＋ channel and voltage-gated Ca^2＋ channel, but also to the voltage-dependent Na＋ channel.