甲基汞对大脑皮层神经细胞内游离钙的影响

Effects of methylmercury on intracellular free calcium content in cerebral cortical neurons

目的 研究甲基汞对急性分离的大脑皮层神经细胞内游离Ca2 + 水平的影响。方法 采用钙离子指示剂Fura 2双波长荧光检测技术。结果 (0 10～ 5 0 0 )× 10 -6mol/L甲基汞可使大脑皮层神经细胞内游离Ca2 + 水平显著升高 ,且有剂量 效应关系。甲基汞升高神经细胞内游离Ca2 + 的作用与胞外Ca2 + 大量内流和胞内储Ca2 + 释放有关 ,且以胞外Ca2 + 内流为主。胞外Ca2 + 内流与N 甲基 D 天冬氨酸受体门控Ca2 + 通道以及电压门控Ca2 + 通道有关 ,而与电压依赖性Na+ 通道无关。结论 甲基汞可使神经细胞内游离Ca2 + 浓度异常升高 ,且与Ca2 + 通道有密切关系。

Objective This study was conducted to explore effects and potential mechanism of methylmercury on concentration of intracellular free calcium (Ca 2+ ) in the acutely isolated cerebral cortical neurons. Methods Calcium ion indicator Fura 2 two wave length fluorophotometry was used to measure concentration of Ca 2+ . Results (0 10～5 00)×10 -6 mol/L of methylmercury could increase level of free intracellular Ca 2+ in cerebral cortical neurons significantly ( P< 0 01), in a dose response manner. Increase in intracellular free Ca 2+ of neurons caused by methylmercury associated with large influx of Ca 2+ outside cells and release of stored Ca 2+ inside cells, especially by influx of Ca 2+ outside cells. Influx of Ca 2+ outside cells associated with Ca 2+ channels regulated by receptor gate and potential gate, but not associated with sodium dependent channel. Conclusion Methylmercury lead to abnormal increase of intracellular free Ca 2+ in neurons, which is closedly related to Ca 2+ channel.