摘要
用膜片钳全细胞记录法研究关附甲素（ＧＡ）对豚鼠单个心室肌细胞钠离子通道电流（Ｉ_（Ｎａ））的作用。结果表明：ＧＡ明显地抑制Ｉ_（Ｎａ），使其最大峰值由８．０２±２．５３ｎＡ降至４．４１±１．８１ｎＡ（ｎ＝８，Ｐ＜０．０１）；使Ｉ_（Ｎａ）的电流－电压曲线上移，但不使其峰值发生偏移；使钠通道灭活曲线左移，明显减慢钠通道灭活后的恢复过程。由此提示ＧＡ与失活态的钠通道结合而抑制Ｉ_（Ｎａ）对Ｉ_（Ｎａ）的阻滞作用为其抗心律失常作用的主要机制。ＧＡ对Ｉ_（Ｎａ）的作用可以用受体调节学说解释。
The effects of Guan-fu base A(GA)on sodium channel current(I_(Na))were investigated in isolated single ventricular cells from guinea pig hearts using patch clamp whole-cell recording,GA reduced In,to 4.41±1.81 nA from 8.02±2.53 nA(n=8,P<0.01).GA shifted up the current-voltage curve but exerted no effects on peak current potential,shifted the sodium availability curve toward more negative potentials,and slowed the time course of recovery from inactivation of sodum channel.These results suggested that GA inhibited I_(Na)by binding to the inactivated state of sodium channel and bolcking effects of GA on I_(Na)were the major mechanism of its antiarrhythmic action.The effects of GA on I_(Na)could be explained by modulated receptor theory.
关键词
单附甲素
抗心律失常
心肌细胞
钠通道
Patch clamp Whole cell recording Sodium current Guan-fu base A
