心肌梗塞后心力衰竭大鼠心脏β3肾上腺素受体的表达及卡维地洛的影响

目的：研究急性心肌梗塞后心力衰竭大鼠心肌中陆肾上腺素受体（β3-AR）表达的变化以及卡维地洛的干预作用。方法：SD大鼠行冠状动脉左前降支结扎术，4周后存活大鼠被随机分为心力衰竭（HF）对照组、美托洛尔（MET）组、卡维地洛（CAR）组3组，另有10只大鼠行假手术（Sham组）。MET组给予美托洛尔6mg／kg·d，CAR组给予卡维地洛3mg／kg·d。Sham组、HF组给予等量生理盐水灌胃。再次饲养8周后所有存活大鼠行血流动力学检查，逆转录聚合酶链式反应（RT—PCR）法测定心肌β3-ARmRNA表达。结果：与Sham组相比，HF组心率（HR）显著增快（P〈0．01），左室收缩压（LVSP）、左室内压最大上升和下降速率（±do／dr）显著降低（P〈0.01），左室舒张末期压（LVEDP）显著升高（P〈0.01）；与HF组相比，MET组、CAR组血流动力学参数得到显著改善（P〈0.01或〈0．05），且以CAR组更为明显。与Sham组相比，HF组β3—ARmRNA表达明显增高（P〈0.01）；与HF组相比。MET组β3-ARmRNA表达无显著变化（P〉0.05），而CAR组β3-ARmR—NA表达率显著下降（P〈0.01）。结论：心力衰竭大鼠心肌中β3-ARmRNA表达增加，卡维地洛能降低β3-ARmRNA的表达，从而改善心功能。

Effect of carvedilol on β3-adrenoceptor mRNA expression in rat ventricle with heart failure after myocardial infarction

Objective.. To study the effect failure （HF） after myocardial infarction of carvedilol on β3 -- adrenoceptor mRNA expression in rat ventricle with heart rats were randomly assigned to HF control er 10 rats were assigned to sham operated Methods： Four weeks after ligating left coronary artery, the surviving SD group and metoprolol （MET） group and carvedilol （CAR） group. The othgroup. 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 （P〈0.01 all） in the HF group. Compared with HF group, the hemo- dynamic index was significant improved in MET group and CAR group （P〈0.05 or 〈0.01）, it was more in the CAR group （P〈0. 05）. Compared with sham group, the expression of β3 --adrenoceptor mRNA was significantly increased in HF group （P〈0.01）. Compared with HF group, the expression of β3- adrenoceptor mRNA was significantly decreased in CAR group （P〈0.01）. There was no significant difference of β3 -- adrenoceptor mRNA between HF group and MET group （P〉0.05）. Conclusion： The level of β3- adrenoceptor mRNA expression remarkably increased in the rats ventricles with heart failure. Carvedilol can decreased the β3 --adrenoeeptor mRNA expression and effectively improve heart function of rats.