Protective effects of endogenous dynor-phin and kappa opioid receptor in ischemic preconditioning against myo-cardium ischemia/reperfnsion injury
AIM: To investigate the effects of ischemic preconditioning on endogenous dynorphin content of blood plasma and mRNA of ventricular myocytes in rats and the protective effects of dynorphin and kappa opioid receptor against myocardium ischemia/ reperfusion injury. METHODS: Forty-eight rats were randomly divided into 6 groups: control group, sham group, ischemic preconditioning group (IPC), ischemia/reperfusion group (I/R), IPC + I/R group and Nor-BNI + IPC + I/R(Nor-BNI, a selective kappa opioid receptor antagonist) (n = 8, each). Radioimmunoassay was employed to measure the dynorphin content of blood plasma and polymerase chain reaction (PCR) was used to measure mRNA of ventricular myocytes. The influence of pre-administration of a selective kappa opioid receptor antagonist before IPC was also observed. RESULTS: The level of dynorphin content of blood plasma significantly increased in IPC group compared with that in 30 min sham group (P ＜ 0.05), but mRNA of ventricular myocytes showed no significant difference. Left ventricular systole pressure (LVSP) and ± dp/dtmax significantly decreased with administration of Nor-BNI (2 mg/kg) at 10 and 30 min of ischemia as well as 30 min of reperfusion (timing from 30 min of ischemia) compared with those in IPC + I/R group (P ＜ 0.05). CONCLUSION: IPC promotes the release of endogeneous dynorphin and increases the level of dynorphin content of blood plasma in rats. Blockade of kappa opioid receptor blunts the protective effects of IPC on the recovery of cardiac function.
ischemic preconditioningmyocardial reperfusion injurgkappa opioid receptorNor-BNIlevel of dynorphin content of blood plasmmRNA of myocardium
NETL
NSTL
万方数据
维普
