硫酸镁对大鼠急性分离海马CA1神经元钠电流的抑制作用

[Inhibition of sodium currents in acutely isolated hippocampal CA1 neurons of rats by magnesium sulfate].

作者信息

Sang Nan, Meng Zi-Qiang

机构信息

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

出版信息

Sheng Li Xue Bao. 2002 Dec 25;54(6):539-43.

PMID:12506330

Abstract

The effects of magnesium sulfate (MgSO4) 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 MgSO4 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 results also showed that 4 mmol/L MgSO4 shifted the steady state activation curve of Na(+) currents towards positive potential (control V(h)=-55.8+/-6.8 mV, MgSO4 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 MgSO4 might be an interpretation for its neuroprotection against damages induced by ischemia and oxygen deprivation.

摘要

采用全细胞膜片钳技术，研究了硫酸镁（MgSO4）对大鼠新鲜分离海马CA1神经元钠电流（Na(+)电流）的影响。结果表明，MgSO4可引起Na(+)电流浓度依赖性和电压依赖性降低。半数抑制浓度（IC(50)）为4.05 mmol/L。该作用与频率无关。结果还显示，4 mmol/L MgSO4使Na(+)电流的稳态激活曲线向正电位方向移动（对照组V(h)=-55.8±6.8 mV，MgSO4组V(h)=-34.2±6.2 mV，n = 8，P<0.01），而斜率因子不变。然而，稳态失活曲线未受影响。这些结果表明，MgSO4对Na(+)电流的阻断可能是其对缺血缺氧损伤具有神经保护作用的一种解释。