山奈酚对急性短暂缺氧时大鼠海马CA_1神经元电压依赖性钾通道的作用  

Effects of kaempferol on voltage-gated potassium currents in CA_1 pyramidal neurons of rat hippocampus in acutely transient hypoxia

作　　者：董敏[1] 肖亮[2] 宋明柯[2] 

机构地区：[1]中南大学药学院药理敦研室,长沙410078 [2]中科院上海药物研究所,上海201203

出　　处：《中南药学》2004年第3期135-138,共4页Central South Pharmacy

摘　　要：目的 研究山奈酚对正常和急性短暂缺氧时大鼠海马CA_1锥体神经元电压依赖性钾通道的作用。方法 急性分离大鼠海马CA_1区锥体神经元,采用全细胞记录。用含有氰化钾(KCN)60μmol·L^(-1)的标准外液灌流模拟细胞缺氧,观察山奈酚对正常和缺氧时海马CA_1区神经元电压依赖性钾通道的作用。结果 山奈酚对正常和缺氧时海马CA_1神经元电压依赖性K^1电流有明显的抑制作用,可同时抑制瞬时外向型钾电流(I_A)和延迟整流性钾电流(I_K)。具有浓度依赖和电压依赖性;山奈酚对I_A的半数抑制浓度(IC_(50))约为50μmol·L^(-1),对I_k的IC_(50)约为 80μmol·L^(-1)。结论 山奈酚对正常和缺氧时大鼠海马CA_1神经元电压依赖性钾通道有抑制作用。其对钾通道的抑制作用可能参与脑缺血保护。OBJECTIVE To investigate the effects of kaempferol on voltage-gated potassium currents in CA_1 pyramidal neurons of rat hippocampus in both normal state and acutely transient hypoxia. METHODS Hypoxia of the neurons was induced by superfused with potassium cyanide (KCN) 60 μmol·L^(-1), and whole-cell recording techniques were used to study the K^+ currents in acutely dissociated rat hippocampal pyramidal neurons in both the normal state and during the hypoxia. RESULTS Kaempferol inhibited both the fast transient (I_A) and delayed rectifier potassium (I_K) currents of the neurons in the normal state and during the hypoxia in concentration-dependent manners.The inhibition was vollage-dependent and reversible. The half-maximum inhibiting concentration (IC_(60)) values of kaempferol on I_A and I_K of the neurons were about 50μmol·L^(-1) and 80 μmol·L^(-1), respectively. CONCLUSIONS Kaempferol is a blocker of voltage-gated potassium channels in pyramidal neurons of rat hippocampus. The electrophysiological effects of kaempferol may be one mechanism of its protective effects on rat hippocampal neurons in acutely transient hypoxia.

关 键 词：山奈酚 急性短暂脑缺氧 大鼠 海马CA1区 电压依赖性钾通道 锥体神经元 神经保护 

分 类 号：R965[医药卫生—药理学]