Effect of captopril on prolongation of action potential duration and reduction Ik in ischemia pig ventricular myocytes / 中国病理生理杂志

ABSTRACT

AIM: To evaluate the effect of captopril on action potential duration and outward delayed rectification potassium current (Ik). METHODS: Action potentials were recorded using a conventional glass microelectrode filled with 3 mol/L KCl solution. Membrane patch clamp whole cell recording technique was used to investigate the Ik current maximum in the holding potential - 50 mV, lasting time 100 ms, command potential + 40 mV. RESULTS: The action potential duration of 30%, 50% repolarization (APD30, APD50) and ERP were significantly prolonged, but APD90 wasn' t prolonged significantly when captopril group compared with ischemic group. The amplitude of Ik increased significantly in ischemic group, but significantly decreased in captopril group and in captopril + ischemic group. The shapes of current - voltage relationship were unchanged among groups, but significantly upward in ischemic group and downward in captopril and captopril + ischemic group. CONCLUSION:Captopril exerts electrophysiologic action due to decreasing delay outward rectification potassium current and prolonging action potential duration of APD30, APD50 and ERP.