RESUMO
Isolated perfused rat hearts were subjected to regional ischemia followed by reperfusion and then tested for responsiveness to acetylcholine (Ach) and nitroglycerin (NTG). The effects of L-Arginine (L-Arg) and NG-monomethyl-L-Arg (L-NMMA) on the endothelium-dependent (ED) and independent (EI) vasodilator were also observed. It was found that both 15 and 30min ischemia followed reperfusion resulted in a decrease in ED vasodilation of Ach. ED vasodilation gradually renewed after 90min reperfusion in the 15min ischemic group, not in the 30min ischemic group. No significant decrease in EI vasodilation of NTG in all groups. L-Arg accelerated the renewing of ED vasodilation of Ach in the 15 min ischemia-reperfusion group, not in the 30min ischemia-reperfusion group. L-NMMA was an inverse action. The results indicate that brief ischemia followed by reperfusion can induce coronary endothelium dysfunction which may be related to the decrease of endothelium derived relaxing factor.