摘要
目的 研究硫酸镁 (MgSO4)对大鼠海马神经元瞬间外向钾电流 (IA)和延迟整流钾电流 (IK)的作用。方法全细胞膜片钳技术。结果 MgSO4可浓度依赖地抑制IA 和IK,半数抑制浓度IC50 分别为 6 30和 7 6 0mmol·L- 1 ;此外还与电压呈依赖性关系 ,但不具有频率依赖性。 6mmol·L- 1 MgSO4非常显著地影响IA 和IK 的激活过程 ,但不改变二者的斜率因子。另外 6mmol·L- 1 MgSO4还非常显著地影响IA 的失活过程 ,但不改变其斜率因子。结论MgSO4抑制大鼠海马神经元的IA 和IK,并改变IA 和IK 的激活过程和失活过程。这可能是其抗缺血缺氧引发的中枢神经系统损伤 ,具有神经保护作用的机制之一。
AIM To study the effect of magnesium sulfate on transient outward K + current (I A) and delayed rectifier K + current (I K) in freshly dissociated hippocampal neurons of rats. METHODS The whole-cell patch clamp techniques were used. RESULTS Magnesium sulfate reversibly reduced the amplitudes of I A and I K in a concentration-dependent and voltage-dependent, but not frequency-dependent manner. Half-blocking concentration (IC 50 ) on I A and I K were 6.30 mmol·L -1 and 7.60 mmol·L -1 , respectively. Magnesium sulfate (6 mmol·L -1 ) affected the activation process of I A and I K. Before and after application of the drug, the half-activation voltages of I A were (7±6) mV and ( -7 ±11) mV (n=10, P<0.01), and the half-activation voltages of I K were (20±6) mV and (28±4) mV (n=10, P<0.01), but the slope factors were not changed. In addition, magnesium sulfate (6 mmol·L -1 ) also affected the inactivation process of I A. Before and after application of the drug, the half-inactivation voltages of I A were ( -65 ±5) mV and ( -89 ±6) mV (n=10, P<0.01). CONCLUSION Magnesium sulfate inhibited I A and I K in freshly dissociated hippocampal neurons of rats, which might contribute to protect the central neuronal system (CNS) against damages induced by ischemia and oxygen deprivation.
出处
《药学学报》
CAS
CSCD
北大核心
2002年第7期510-515,共6页
Acta Pharmaceutica Sinica
基金
国家自然科学基金资助项目 ( 30 0 70 6 40 )
