Role of verapamil [calcium channel blocker] and lisinopril [angiotensin converting enzyme inhibitor] on myocardial tolerance to acute ischaemia

ABSTRACT

This work aims to clarify the role of calcium channel blocker [verapamil] and angiotensin-converting enzyme inhibitor [lisinopril] on myocardial ischemia reperfusion injury. The study was done using isolated rabbits hearts and Langendroffs apparatus for recording myocardial contractility, heart rate and coronary flow, also glucose uptake by coronary slices was estimated by glucose enzymatic kit. The work included 4 groups; Group A to study effect of ischemia and reperfusion on mentioned parameters, Group B to study effect of verapamil and lisinopril on tested parameters. Group C to study the effect of 5 minutes pre-ischaemia administration of verapamil and lisinopril on tested parameters and Group D to study the effects of administration of verapamil and lisinopril with reperfusion on parameters mentioned before. Results concluded that global ischaemia decreased the myocardial contractility and heart rate but increases glucose uptake, verapamil is a potent drug used to decrease myocardial contractility, heart rate and increase coronary flow in ischaemic hearts. Lisinopril is a drug of choice to improve contractility and heart rate when administered preischaemic or with reperfusion. Verapamil is a drug of choice to improve coronary flow when administered preischaemic or with reperfusion. There is no preference between the 2 drugs when given preischaemic on increasing glucose uptake. So calcium, angiotensin and O2 free radicals are important mediators of ischaemic reperfusion injury as their modulation by the verapamil and lisinopril significantly improve ischaemia reperfusion induced changes in myocardial contractility, heart rate, coronary flow and glucose uptake