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目的通过比较对不同跨膜离子电流作用的效能、效价,探讨传统中药苦参碱抗心律失常作用弱于西药奎尼丁、维拉帕米的原因,确定苦参碱作用的最佳靶点.方法应用全细胞膜片钳技术记录大鼠单个心室肌细胞动作电位和离子电流.首先应用乌头碱诱发心肌离子电流改变,然后观察苦参碱、奎尼丁和维拉帕米对乌头碱诱发离子电流和动作电位改变的作用.结果乌头碱1μmol·L-1诱发大鼠单个心室肌细胞动作电位和离子电流显著变化.乌头碱延长动作电位时程同时增加钠、L-型钙电流和内向整流钾电流.苦参碱100μol·L-1恢复乌头碱诱发的改变,但作用弱于奎尼丁和维拉帕米.结论应用乌头碱打破了心室肌细胞离子通道的平衡,而应用苦参碱明显抑制乌头碱诱发的改变,但其效能效价低于常用的奎尼丁和维拉帕米.“,”Aim To explore the reason that the antiarrhythmic effect of the extract of traditional Chinese medicinal herb, matrine, is weaker than quinidine and verapamil by comparision of the effect and efficacy of mattine on various kinds of transmembrane ionic currents with those of quinidine and verapamil; and to demonstrate the best targets for antiarrhythmic drugs. Methods Whole-cell patch-clamp techniques were used to record the action potential and ionic currents in single cells of rat ventricular myocytes. Aconitine was used to induce the changes of ionic currents, then study the effects of matrine and quinidine, verapamil on aconitine-induced imbalanced channel currents and action potential. Results Aconitine 1cytes. APD was significantly prolonged by aconitine. Simultaneously, aconitine increased sodium, L-type calcium and infrom ( - 70.2 + 10.5) pA/pF to ( - 39.6 + 4.0) pA/pF ( n = 5, P ＜ 0.05 vs aconitine); L-type calcium current ( ICa-L )from (20.4+3.8) pA/pF to ( - 12.9+2.9) pA/pF (n =6, P ＜0.01); the inward rectifier potassium current (Ik1) from(-32.2 + 1.08) pA/pF to ( - 24.0 + 3.4) pA/pF ( n = 6, P ＜ 0.01), and action potential duration. The reversal effects of quinidine and verapamil on aconitine-induced changes of APD and ionic currents were more marked than matrine. Conclusion Aco-nitine significantly disturbs the normal equilibrium of ion channels in ventricular myocytes. It induces changes significantly suppresses aconitine-induced changes of APD and ionic currents. The potency and efficacy of inhibitory effect of matrine are markedly weaker than those of commonly used verapamil and quinidine.