Abstract: Objective To investigate pravastatin effects of Ito after acute myocardial infarction(AMI) in rat. Methods AMI model induced by the left anterior descending coronary artery (LAD )ligation in rats，randomly divided into 24-hour group, 1-week group, 4-week group and pravastatin group（20mg/kg）．Accordingly，the sham-operation group was established． Kv1.4、Kv4.2 and Kv4.3 mRNA and protein were measured with free right ventricular wall of each group using real-time polymerase chain reaction (real time-PCR) and western blot．Results The expression of Kv1.4 mRNA and protein was up-regulated after 24 hours in AMI; the expression of Kv4.2 and Kv4.3 mRNA and protein was down-regulated, the former lowest in 4-week group and the latter lowest in 24-hour group; Kv1.4 mRNA（P＜0.01） and protein（P＜0.05） of pravastatin group was lower than 4-week group, Kv4.2(P＜0.05，P＜0.05) and Kv4.3(P＜0.01，P＜0.05) mRNA and protein of pravastatin group were higher than 4-week group. Conclusion The expression of Kv1.4 mRNA and protein increased while Kv4.2 and Kv4.3 mRNA and protein depressed after AMI in rat, pravastatin may decrease the variance of Ito.

Key words: acute myocardial infarction, transient outward current, pravastatin, rat