Effect of carvedilol on β_3-adrenoceptor mRNA expression in rat ventricle with heart failure after myocardial infarction

Objective:To study the effect of carvedilol on β3-adrenoceptor mRNA expression in rat ventricle with heart failure(HF) after myocardial infarction.Methods:Four weeks after ligating left coronary artery, the surviving SD rats were randomly assigned to HF control group and metoprolol (MET) group and carvedilol (CAR) group.The other 10 rats were assigned to sham operated group.Metoprolol was treated orally with 6 mg/kg·d in MET group and carvedilol was treated orally with 3 mg/kg·d in CAR group.Isometric saline was treated orally in Sham group and HF group.After 8 weeks of therapy, hemodynamic studies and the expression of β3-adrenoceptor mRNA were compared.Results:Compared with Shan group, Heart rates and left ventricular end diastolic pressure (LVEDP) were significantly increased while the left ventricular systolic pressure (LVSP) and left ventricular pressure maximal rate of rise or fall(dp/dt) were significantly decreased (P0.01 all) in the HF group.Compared with HF group, the hemodynamic index was significant improved in MET group and CAR group (P0.05 or 0.01),it was more in the CAR group(P0.05).Compared with sham group, the expression of β3-adrenoceptor mRNA was significantly increased in HF group (P0.01 ).Compared with HF group, the expression of β3-adrenoceptor mRNA was significantly decreased in CAR group(P0.01 ).There was no significant difference of β3-adrenoceptor mRNA between HF group and MET group(P0.05).Conclusion:The level of β3-adrenoceptor mRNA expression remarkably increased in the rats ventricles with heart failure.Carvedilol can decreased the β3-adrenoceptor mRNA expression and effectively improve heart function of rats.