[The effect of stimulation of cardiac delta1-opioid receptors on the resistance of isolated heart to the action of ischemia and reperfusion].

Preliminary stimulation of cardiac delta1-opioid receptors by DPDPE addition at a concentration of 0.1 mg/liter to the perfusion solution decreased the incidence of reperfusion arrhythmias and the reperfusive destruction of cardiac cells. At the same time, the activation of cardiac delta1-opioid receptors resulted in a decrease in myocardial contractility both in the pre-ischemic period and upon restoration of the coronary flow. Pretreatment with naltriondole (a delta-receptor antagonist) or with cyclopiazonic acid (a specific inhibitor of Ca2+ uptake in sarcoplasmic reticulum) completely abolished the antiarrhythmic, cardioprotective, and inotropic effects of DPDPE. It is suggested that the antiarrhythmic, cardioprotective, and inotropic effects of DPDPE is related to the cardiac delta1-opioid receptor activation and Ca2+ transport alteration on the level of sarcoplasmic reticulum.