The effects of the angiotensin converting enzyme inhibitors (ACEI) captopril and lisinopil on injury induced by
ischemia/reperfusion
were investigated in the isolated working heart and Langendorff perfused rat heart.
Ischemia/reperfusion was produced by ligation of the left descending branch of the coronary artery for 15 minutes followed by reperfusion for 1 or 5 minutes.The high doses of captopril (200 μmol/L) and lisinopril (0. 1μmol/L) reduced the incidence of ventricular fibrillation following ischemia/reperffusion in both working and Langendorrff perfused hearts. Furthermore,both ACEI (captopril. 200 μmol/L ;lisinopril,0. 1 μmol/) attenuated the myocardial noradrenalin and calcium concentration following ischemia/reperfusion in Langendorff perfused hearts.In contrast,only captopril reduced the formation of free fadicals following ischemia.reperfusion in Langendorff perfused hearts. Also the formation of superoxide anion in vitro by UV irradiation of a riboflavin/DMPO mixture was only diminished by captopril.We conclude that both captopril and lisinopril protect the myocardium against injury induced by ischemia/reperfusion.The beneficial effects of captopril probably depend on scavenging of free radicals and on prevention of calcinm overload and noradrenalin release,whereas the beneficial effects of lisinopril probably only depends on prevention of calium overload and noradrenalin relese induced by ischemia/reperfusion.