RESUMO
ObjectiveTo investigate the effect of β-adrenoceptor (β-AR) blockers on G protein and heart function changes in rats with acute myocardial infarction (AMI) MethodsWistar rats with AMI induced by left anterior descending coronary branch ligation were randomly divided into compared with sham operation group. Eight weeks after therapy, hemodynamics was assessed by inserting catheters and the level of G protein was detected by Western blot analysis. ResultsCompared with the sham operation group, systolic blood pressure(SBP), diastolic blood pressure (DBP), left ventricular systolic pressure(LVSP) and left ventrieular pressure maximal rate of rise and fall(±dp/dtmax) in AMI group were significantly decreased, while left ventricular end diastolic pressure (LVEDP) and Gs and Gi protein levels were significantly increased (all P<0.05). Compared with AMI group, LVSP and ± dp/dtmax were increased, but LVEDP and Gi protein level were significantly decreased in metoprolol and carvedilol group. LVEDP and Gi protein level were decreased in carvedilol group compared with metoprolol group. ConclusionsCarvedilol can effectively suppress the change of G protein and improve the heart function after AMI, and the effect is better than that of metoprolol. This may be related with its β2-AR blocking effect.