Blockade of opioid receptors and the response of the heart to injury during ischemia and reperfusion

The role of opioid receptors in regulation of response of the heart to total ischemia and reperfusion was studied in experiments on isolated perfused rat hearts. Duration of ischemia was 45 min and that of reperfusion - 60 min. It was found that μ-receptors played an important role in regulation of end-diastolic pressure as blockade of these receptors prevented development of postischemic contracture. At the same time blockade of μ-receptors augmented reperfusion injury of sarcolemma. δ-receptors were not found to play a marked role in pathogenesis of ischemic and reperfusion myocardial injury. Inhibition of κ-receptors facilitated recovery of cardiac contractility during reperfusion. It also decreased the level of creatine kinase in effluent solution what was indicative of a reduction of damage of membranes of cardiac cells.