Role of Endogenous Opioid Receptor Agonists in Regulation of Heart Resistence to the Arrhythmogenic Action of Short-Term Ischemia and Reperfusion

Preliminary selective block of mu-, delta1-, delta2-, and kappa-opioid receptors had no effect on the incidence of ventricular arrhythmias during 10-min coronary occlusion-reperfusion in ketamine-narcotized rats. Repetitive short-term immobilization of rats for 2 weeks improved heart resistance to the arrhythmogenic action of coronary occlusion and reperfusion. Selective mu-opioid receptor antagonist CTAP completely abolished, while selective delta- and kappa-opioid receptor antagonists did not modulate the antiarrhythmic effect of adaptation. Probably, endogenous agonists of mu-opioid receptors play an important role in the adaptive improvement of heart resistance to arrhythmogenic factors, but are insignificant for the modulation of heart resistance to the arrhythmogenic action of short-term local ischemia-reperfusion in non-adapted animals.