莲心碱对豚鼠心室肌细胞动作电位及钠与钙电流的影响

Effects of Liensinine on Action Potentials and I_(Na) , I_(Ca-L) in Guinea Pig Ventricular Myocytes

为探讨莲心碱 (liensinine,L ien)对心肌离子流的影响及抗心律失常作用机制。采用全细胞膜片钳技术 ,记录了 L ien对单个豚鼠心肌细胞动作电位 (AP)及纳电流 (INa)与 L -型钙电流 (ICa- L)的影响。 L ien 3～ 30μmol/ L 可剂量依赖性地降低 AP幅度 (APA)、静息电位 (RP) ,延长 AP时程。 L ien10 ,30 μm ol/ L 分别使 INa及 ICa- L从给药前的 (8.6± 2 .3) n A和 (75 8± 177) p A降至 (5 .4± 1.7)、(2 .2± 1.6 ) n A和 (335± 12 2 )、(137±10 0 ) p A。L ine10 μmol/ L 抑制 INa和 ICa- L的 I- V曲线并使后者的峰值电流电位略右移。结果表明 L ien有钠、L -型钙通道阻滞作用 。

The effects of liensinine (Lien) on the action potentials (AP) and ionic currents and the mechanism of its antiarrhythmic action were evaluated. Using whole cell recording patch clamp technique, the AP, sodium channel current (I Na ), and L type calcium channel current (I Ca L ) were studied in guinea pig ventricular myocytes. Lien 3～30 μmol/L was shown to reduce dose dependently the AP amplitude (APA), resting potential (RP) and prolong the AP duration. Lien 10 and 30 μmol/L decreased I Na and Ca L respectively from (8 6±2 3) nA and (758±177) pA of the control level to (5 4±1 7),(2 2±1 6) nA and (335±122),(137±101) pA. In addition, Lien 10 μmol/L could inhibit the I～V curves of I Na and I Ca L and slightly shift the maximum current potential of the latter to the right. The results demonstrated that Lien could inhibit sodium and calcium channel currents, which may partially explain the mechanism of its extensive antiarrhythmic actions.