淫羊藿苷对兔心室肌细胞L-型钙电流的影响

目的:利用膜片钳技术研究淫羊藿苷(ICA)对兔单个心室肌细胞L-型钙电流(ICa,L)的影响。方法:采用酶解法分离兔单个心室肌细胞,应用全细胞膜片钳技术观察10,20,40μmol/L的ICA对心室肌细胞ICa,L的作用。结果:①10,20,40μmol/L的ICA使兔心室肌细胞ICa,L最大峰电流密度从(15.81±1.23)pA/pF分别降至(11.27±0.89)pA/pF,(9.48±0.85)pA/pF和(6.87±0.81)pA/pF(n=6,P<0.05),抑制率分别为28.7%,40.0%和56.5%;ICA使ICa,L的电流-电压曲线上移,但不改变其基本形状;②20μmol/L ICA可以使钙通道稳态失活曲线左移并可减慢L-型钙通道失活后的恢复过程。结论:ICA对ICa,L具有浓度依赖性阻滞作用,这可能是其抗心律失常的重要机制之一。

Effect of Icariine on L-type Calcium Current in Isolated Ventricular Myocytes

Objective: To observe the effect of icariine on L-type calcium current in isolated rabbit ventricular myocytes by using whole-cell patch clamp technique.Methods: Single ventricular cell of rabbit was obtained by an enzymatic disassociation method.The whole-cell patch clamp technique was used to record the effect of icariine(ICA) on L-type calcium current(ICa,L) of rabbit ventricular myocytes.Results: ① 10,20 and 40 μmol/L ICA decreased peak Ica,L from(15.81±1.23) pA/pF to(11.27±0.89),(9.48±0.85) and(6.87±0.81) pA/pF,respectively(n=6,P<0.05).Peak Ica,L was reduced by 28.7%,40.0% and 56.5%,respectively by ICA at 10,20 and 40 μmol/L.In addition,ICA could up-shift the I-V curves of ICa,L without changing their basic shape(n=6,P<0.05);② 20 μmol/L ICA could delay the recovery time course of ICa,L from inactive state and cause inactivation curve moving leftward.Conclusion: ICA blocks ICa,L in a concentration-dependent manner,which may contribute to its anti-arrhythmia effect.