Effect of β blockers on β 3 -adrenoceptor mRNA Expression in the Rats with Chronic Heart Failure

Objectives To investigate the changes of β3-adrenoceptor (β3-AR) mRNA expression in the rats with chronic heart failure (CHF), and to explore the effect of β blockers (βBs) on β3 mRNA expression. Methods Thirty-four rats were randomly divided into Sham group (n = 10) and heart failure group (n = 24). Rat model was established by aortic constriction. The survival rats in heart failure group were divided into heart failure control group (HF group, n = 6), metoprolol group (MET group, n = 8) and carvedilol group (CAR group, n = 8) three months after operation. Metoprolol tartarte was started orally with 12 mg·kg-1·d-1, carvedilol with 6 mg·kg-1·d-1, isometric saline was started in HF group. After three months of drug therapy, measurement of hemodynamics, index of ventricular mass, the level of β3-AR mRNA expression were performed. Results Compared with Sham group, left ventricular end systolic pressure (LVESP), and the absolute values of maximal rate of rise and fall ( ± dp/dtmax) of left ventricular pressure were all significantly decreased (P 0.05), but significant decrease could be seen in CAR group (P < 0.01). The level of β3-AR expression in left ventricle was greater than that in right ventricle whether in the failing heart or in the non-failing heart. Compared with Sham group, the level of β3-AR mRNA expression was significantly increased in HF group (P < 0.01). The levels of β3-AR mRNA expression showed a remarkable decrease in CAR group(P &lt