Effects of norepinephrine preconditioning on myocardial expression of HSP70 and nitric oxide and nitric oxide synthase in isolated rat heart

Objective:To investigate the synthesis of heat shock protein 70(HSP70) induced by norep-inephrine preconditioning on donor heart and the expression of myocardial cell nitric oxide(NO) and nitric oxide synthase(NOS) of isolated rat heart.Methods:18 Wistar rats were randomly divided into 2 groups.Con-troll group(C,n=9),Normal saline 0.5 ml was injected intraperitoneally and 24 hours later isolated hearts were stored in 4℃ for 3 hours with Histidine-tryptophan-ketoglutarate(HTK) solutions,and then isolated hearts were perfused for 2 hours by Langendorff model.Experimental group(E,n=9),Noradrenaline Bitar-trate 3.1 μmol/kg(0.53 mg/kg) was injected intraperitoneally and 24 hours later isolated hearts were stored in 4 ℃for 3 hours with HTK,and then isolated hearts were perfused for 2 hours with Krebs-Henseleit(K-H) solutions by Langendorff model.Myocardial HSP70 content,the expression of NO、NOS and related biochemical indicators were detected.Results:HSP70、NO and NOS in E group are higher than those in C group and biochemical indicators in E group are better than those in C group.Conclusion:This study demonstrates that norepi-nephrine preconditioning can induce the high expression of HSP70,and it has obvious protection on donor heart,and it can markedly affect the expression of NO and NOS of isolated rat heart,it is perhaps one of important factors for myocardial protection.