The Role of ATP-sensitive Potassium Channels in Ischemic Preconditioning of Rat Hearts

Objective:To study the role of ATP sensitive potassium channels in ischemic preconditioning of isolated rat hearts.Methods:Hearts were isolated from male SD rats,and perfused on a Langendorff apparatus.Rat hearts were pretreated with 3 min global ischemia followed by 5 min reperfusion for three times or as ischemic preconditioning and perfused for 30 min as control.The K ATP channel blocker——glibenclamide (10 μmol/L) or opener——pinacidil (50 μmol/L) was preperfused in this stage.Then the left coronary artery was occluded for 20 min and reperfused for 60 min to observe the effects of drugs on myocardial infarct size and arrhythmic scores.Results:The action of ischemic preconditioning was blockaded by glibenclamide,and pinacidil failed to mimic the ischemic preconditioning.But pinacidil treatment just before ischemia was cardioprotective.Conclusions:It seems that K ATP channels take part in the promotion of ischemic preconditioning and the cardioprotective mechanisms in rat hearts,although they are not the trigger.