淫羊藿苷对兔心室肌细胞L-型钙电流的影响

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

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。

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 umol/L ICA decreased peak Ico,L from （15.81±1.23） pA/pFto （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 umol/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 umol/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.