[The mechanism of the anti-arrhythmia action of opioid receptor agonists and antagonists].

Enkephalins were injected intravenously at a dose of 0.1 mg/kg 15 minutes or 6 hours before adrenalin or CaCl2 injection. Enkephalins were reported to prevent adrenal ventricular extrasystoles but not to influence CaCl2-induced dysrhythmias. Maximum antiarrhythmic effect of enkephalins was demonstrated 6 hours later after the intravenous injection. Naloxone at a dose of 2 mg/kg and morphine at a dose of 1.5 mg/kg prevent adrenal arrhythmias 15 min and 6 hours later after injection. We believe that peripheral delta opiate receptors activation by enkephalins as well as the blockade of non-identified opiate receptors by naloxone prevent arrhythmias.