[INVOLVEMENT OF 5-OPIOID RECEPTORS IN THE INCREASED RESISTANCE OF HEART AND MITOCHONDRIA TO IMPACT OF ISCHEMIA-REPERFUSION AFTER ADAPTATION TO CHRONIC CONTINUOUS HYPOXIA].

It was investigated the involvement of cardiac Ϭ-opioid receptors (OR) in increasing the resistance of the heart and myocardial mitochondria to ischemia-reperfusion after adaptation rats to chronic continuous normobaric hypoxia (CCNH). Rats were subjected to CCNH for 21 days at 12 % O2. It was evoked global ischemia (45 minutes) and reperfusion (30 minutes) of the isolated perfused heart. Adaptation to CCNH promoted a reduction of creatine kinase release from necrotic cardiomyocytes during reperfusion and improved reperfusion recovery of heart contractility. Mitochondrial respiratory and state of MPT pore were more resistant to ischemia-reperfusion in adapting rats. Perfusion of isolated hearts with TIPP(0) (30 nM/l, a selective Ϭ-OR-antagonist) or naltriben (1 nM/l, a selective 52-OR-antagonist) completely eliminated the cardioprotective effect of CCNH. BNTX (1 nM/l, a selective Ϭ-OR-antagonist) had no effect on the cardioprotective effect of CCNH. This data suggest that cardiac 52-OR involved in the increased resistance of the heart and mitochondria to ischemia-reperfusion after adaptation rats to CCNH.