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硫酸镁对大鼠海马CA_(1)区神经元钠电流的抑制作用

桑楠, 孟紫强

山西大学环境医学与毒理学研究所.山西,太原 030006

摘要

利用全细胞膜片钳技术研究了硫酸镁(MgSO_(4))对大鼠海马CA_(1)区神经元钠电流的影响。结果表明,MgSO_(4)可浓度依赖和电压依赖地抑制钠电流,半数抑制浓度为4.05mmol/L。这一抑制作用与刺激频率无关。结果还表明,4mmol/L MgSO_(4)不影响钠电流的失活过程,却使半数激活电压由-55.8±6.8mV变为-34.2±6.2mV(n=8,P<0.01),而激活曲线的斜率因子不变。结果提示,MgSO_(4)抑制大鼠海马CA_(1)区神经元的钠电流可能是其抗缺血缺氧造成的中枢神经系统损伤的机制之一。

关键词： 海马CA1区神经元; 全细胞膜片钳技术; 硫酸镁(MgSO4); 钠电流

Inhibition of sodium currents in acutely isolated hippocampal CA_(1) neurons of rats by magnesium sulfate

Sang Nan, Meng Ziqiang

Institute of Environmental Medicine and Toxicology,Shanxi University.Taiyuan 030006,Shanxi

Abstract

The effects of magnesium sulfate (MgSO_(4)) on sodium currents (Na~(+) currents) were studied in freshly dissociated hippocampal CA_(1) neurons of rat using the whole-cell patch-clamp technique. The results indicated that MgSO_(4) caused a concentration-dependent and voltage-dependent decrease in Na~(+) currents. The half-inhibitory concentration (IC_(50)) was 4.05 mmol/L. This action was frequency-independent. The result also showed that 4 mmol/L MgSO_(4) shifted the steady state activation curve of Na~(+) currents towards positive potential (control V_(h)=-55.8+-6.8 mV, MgSO_(4) V_(h)=-34.2+-6.2 mV, n=8, P<0.01) without changing the slope factor. However, the steady state inactivation curve was not affected. These results suggest that blockade of Na~(+) currents by MgSO_(4) might be an interpretation for its neuroprotection against damages induced by ischemia and oxygen deprivation.

Key words: Hippocampus;CA_(1) neuron;Patch-clamp technique;Magnesium sulfate[MgS0_(4)]

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引用本文：

桑楠, 孟紫强. 硫酸镁对大鼠海马CA_(1)区神经元钠电流的抑制作用[J]. 生理学报 2002; 54 (6): .

Sang Nan, Meng Ziqiang. Inhibition of sodium currents in acutely isolated hippocampal CA_(1) neurons of rats by magnesium sulfate. Acta Physiol Sin 2002; 54 (6): (in Chinese with English abstract).