The Expression Of Kappa-opioid Receptor In Myocardium And Its Effects On Myocardial Function In Cardiac Arrest And Cardiopulmonary Resuscitation Rats

To investigate the expression of kappa-opioid receptor (κ-OR) in myocardium in cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). The effects ofκ-OR expressions on postresuscitation myocardial function were further discussed to provide experimental evidences for improving postresuscitation myocardial function. An asphyxia-induced CA/CPR rat model was utilized. The expressions ofκ-OR mRNA and protein in myocardium were detected resptively after 5min,6min or 7min of asphyxia and CA/CPR. The expressions ofκ-OR mRNA and protein in myocardium were also detected in the same model (7min of asphyxia and CA/CPR) with epinephrine or epinephrine plus Shengfu treatment during CPR. The hemodynamic data of HR, MAP, dP/dt40, LVEDP and-dP/dtmax were recorded. The relationship betweenκ-OR expression and postresuscitation myocardial function was further discussed. Aκ-OR agonist, pentazocine, was infused in different phase of ischemia or reperfusion (I/R) in Langendorff-perfused isolated rat hearts. The hemodynamic data of HR, dP/dtmax, LVDP,-dP/dtmax and the episodes of ventricular arrhythmia were recorded.Our results demonstrated that the expressions ofκ-OR mRNA and protein in myocardium were significantly increased in CA/CPR rats in comparison to control rats, theκ-OR expression was related to the severity of postresuscitation myocardial dysfunction, and the myocardial protection could be achieved throughκ-OR upregulation. In the setting of isolated heart, activation ofκ-OR could reduce the severity of post-ischemic myocardial dysfunction; better myocardial protection was observed whenκ-OR agonist was ultilized in the early phase of ischemia.