δ-Opioid Receptor as a Molecular Target for Increasing Cardiac Resistance to Reperfusion in Drug Development

An analysis of published data and the results of our own studies reveal that the activation of a peripheral δ(2)-opioid receptor (δ(2)-OR) increases the cardiac tolerance to reperfusion. It has been found that this δ(2)-OR is localized in cardiomyocytes. Endogenous opioids are not involved in the regulation of cardiac resistance to reperfusion. The infarct-limiting effect of the δ(2)-OR agonist deltorphin II depends on the activation of several protein kinases, including PKCδ, ERK1/2, PI3K, and PKG. Hypothetical end-effectors of the cardioprotective effect of deltorphin II are the sarcolemmal K(ATP) channels and the MPT pore.