Activation of kappa-opioid receptor as a method for prevention of ischemic and reperfusion arrhythmias: role of protein kinase C and K(ATP) channels.

Intravenous pretreatment with kappa-opioid receptor antagonist (-)-U-50,488 (1 mg/kg) improved heart resistance to the arrhythmogenic effect of coronary occlusion and reperfusion. Selective kappa1-opioid receptor antagonist norbinaltorphimine and nonselective blocker of peripheral opioid receptors methylnaloxone abolished this antiarrhythmic effect. Preliminary blockade of protein kinase C with chelerythrine or inhibition of ATP-dependent K+ channels (K(ATP) channels) with glybenclamide abolished the antiarrhythmic effect of kappa-opioid receptor activation. Selective inhibitor of sarcolemmal K(ATP) channels did not modulate the kappa-opioid receptor-mediated increase in cardiac electrical stability. Our results suggest that protein kinase C and mitochondrial K(ATP) channels play an important role in the antiarrhythmic effect associated with activation of peripheral kappa-opioid receptors.