QT对豚鼠单一心室肌细胞钙离子电流的影响

EFFECTS OF CHITOSAN ON CALCIUM CURRENT IN SINGLE VENTRICULAR CELLS OF GUINEA PIGS

应用全细胞膜片钳制技术观察了QT村豚鼠单一心室肌细胞钙离子电流（Ica）的影响。结果显示：QT能明显增加心室肌细胞的Ca2+内流，使Ica增大。此作用有明显的电压依赖性，在峰电流电压下作用最明显，而对其反转电位无明显影响。在指令电位0mV时，浓度为500mg·L-1、lg·L-1、2g·L-1的QT分别使Ica增加9．5％、29．3％和523％（分别P＜0．10、P＜0．05、P＜0．01），EC50约1g·L-1。QT对Ica的作用具有可复性。上述结果揭示；QT以电压依赖和浓度依赖的方式增加心肌细胞的Ca2+内流，此作用可能是其治疗充血性心力衰竭的机制之一。

With patch clamp method,the effects of QT on slow inward calcium current (Ica) were investigated in single ventricular cells of guinea pigs. QT 0. 5、1.0、2.0g·L-1 reased Ica by 9. 5% 、29.3% and 52.3%, respectively, EC50 and maximal effective concentration was near 1. 0g·L-1and 2. 5g·L-1.QT reased Ica in a dose-and voltage-dependent mode,but had little effect on reversal potential. Those results show QT can open the calaium channel of ventricular cells.