The Effects And Mechanisms Of One Of The Third Generation β-blocker Carvedilol On Rat Myocardial Ischemia-reperfusion Injury Model Compared With Metoprolol And Propranolol: From The Role Of Gap Junctional Intercellular Communication And Cardiomyocyte Con

[Objective] To study whether Carvedilol, one of the third generation β-blockers has protection effects against acute myocardial ischemia and reperfusion injury(IRI), then to compare with the first and second generation β-blockers such as Metoprolol and Propranolol, and then to explore the mechanism of its anti-IRI effects from the role of cardiolmyocyte gap junctional intercellular communication(GJIC) and connexin 43(CX43).[Methods] 1. Male SD rat were divided randomly into five groups, sham operation group(Sham), myocardial ischemia and reperfusion group(IRI), Carvedilol group(CVD), Metoprolol group(Meto) and Propranolol group(Prop). The left anterior descending branch of coronary artery was ligatured for 30 minutes, then reperfused it for 4 hours to build myocardial ischemia and reperfusion injury model. After 4 hours reperfusion, the incidence of ischemia and reperfusion-induced arrhythmia were calculated; hemodynamic parameters, such as left ventricular peak pressure(LVP), left ventricular end diastolic pressure (LVEDP), left ventricular developed pressure(LVDP=LVP-LVEDP) and peak systolic or diastolic velocity(±dp/dt) were recorded; myocardial enzymes such as creatine phosphokinase(CK), lactate dehydrogenase(LDH), superoxide dismutase (SOD)...