RESUMO
We analyzed the role of opioid receptors in the conditioning effect of continuous normobaric hypoxia on bioenergetics of the heart subjected to ischemia/reperfusion injury. Male Wistar rats were adapted to a 21-day continuous normobaric hypoxia (12% pO2). Then, the hearts were isolated and subjected to 45-min total ischemia followed by 30-min reperfusion. Damage to the myocardium was assessed by activity of creatine phosphokinase in the perfusate. Experiments on isolated mitochondria showed that ischemia/reperfusion injury decreased the respiration rate in state 3 (V3), the ratio of added ADP and oxygen consumption in respiration state 3 (ADP/O ratio), the mitochondrial potential across the inner membrane (Δψ), and Ca2+ binding capacity of mitochondria. In addition, ischemia/reperfusion injury decreased myocardial ATP. Preventive continuous normobaric hypoxia pronouncedly moderated these adverse effects of reperfusion. It was found that its protective effects were related to activation of cardiac µ- and δ2-opioid receptors.
Assuntos
Metabolismo Energético/fisiologia , Hipóxia/metabolismo , Mitocôndrias Cardíacas/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Receptores Opioides/fisiologia , Adaptação Fisiológica/efeitos dos fármacos , Adaptação Fisiológica/fisiologia , Animais , Compostos de Benzilideno/farmacologia , Metabolismo Energético/efeitos dos fármacos , Coração/efeitos dos fármacos , Masculino , Mitocôndrias Cardíacas/efeitos dos fármacos , Miocárdio/metabolismo , Naltrexona/análogos & derivados , Naltrexona/farmacologia , Antagonistas de Entorpecentes/farmacologia , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologia , Ratos , Ratos WistarRESUMO
The course of treatment with combined adaptogenic plant preparation Tonizid improved mouse survival under conditions of hypobaric hypoxia and reduced the necrotic zone/risk zone ratio during ischemia and reperfusion in rats under conditions of artificial ventilation. The test preparation decreased the size of the necrotic zone, but had no effect on the size of the risk zone. Tonizid prevented ventricular fibrillation during coronary occlusion and exhibited antihypoxic, cardioprotective, and antifibrillation properties.