镁对大鼠急性分离海马CA1神经元钠电流的阻断作用。

Blockade by magnesium of sodium currents in acutely isolated hippocampal CA1 neurons of rat.

作者信息

Sang Nan, Meng Ziqiang

机构信息

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

出版信息

Brain Res. 2002 Oct 18;952(2):218-21. doi: 10.1016/s0006-8993(02)03217-1.

DOI:10.1016/s0006-8993(02)03217-1

PMID:12376182

Abstract

The effects of magnesium (MgSO(4)) on sodium currents (Na(+) currents) in freshly dissociated rat hippocampal neurons were studied using the whole-cell patch clamp techniques. MgSO(4) caused a concentration-dependent and voltage-dependent reversible decrease of Na(+) currents. The half-blocking concentration (IC(50)) of MgSO(4) on Na(+) currents was 4.05 mM. But the action was frequency-independent. In addition, 4 mM MgSO(4) shifted the steady state activation curve of Na(+) currents toward positive potential (control V(h)=-55.83+/-6.79 mV, MgSO(4)V(h)=-34.15+/-6.18 mV, n=8, P</=0.01 without changing the slope factor). However, the steady state inactivation curve was not affected. These results suggested that blockade of MgSO(4) on Na(+) currents 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）对新鲜分离的大鼠海马神经元钠电流（Na⁺电流）的影响。MgSO₄ 引起 Na⁺电流浓度依赖性和电压依赖性的可逆降低。MgSO₄ 对 Na⁺电流的半阻断浓度（IC₅₀）为 4.05 mM。但其作用与频率无关。此外，4 mM 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)= -55.83 ± 6.79 mV，MgSO₄ 组 V(h)= -34.15 ± 6.18 mV，n = 8，P≤0.01，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⁺电流的阻断作用可能是其对缺血缺氧诱导损伤具有神经保护作用的一种解释。