Heterogeneous of potassium currents in free wall myocytes from the infarcted rabbit ventricle and regression effects of imidapril

Objective To define the heterogeneous changes of ion channels in the noninfarcted myocardium after myocardial infarction in rabbit and effects of imidapril.Mehods Rabbits with left coronary artery ligation were prepared and allowed to recover for 8 wk.Myocytes were isolated from subendocardial,midmyocardial and subepicardial regions of the noninfarcted left ventricular free wall.Ion currents were recorded with whole-cell patch clamp way.Results The densities of the transient outward K+ currents (I to) and the inward rectifier K+ currents (I K1) were greatly reduced in midmyocardium and subepicardium while two currents reduced gently in subendocardium.The densities of the delayed rectifier K+ currents (I K) were reduced in noninfarcted three layers similarly.Imidapril could reverse the changes of membrane currents in healed myocardial infarction cells and depress the dispersion of repolarization.Conclusions The heterogeneities of K currents are enhanced in noninfarcted area.Normalization of heterogeneous changes of repolarization after treatment with imidapril was observed.