PROTECTIVE ROLE OF IMMOBILIZATION ON OUABAIN-INDUCED ARRHYTHMIAS

The effects of the opioid-type stressor; immobilization, on severity o f ounbain-induced cardiac arrhythmias and the possible involvement of serum catecholamines were investigated in rats. Immobilization signifi cantly reduced the number of ventricular premature beats and the incid ence of ventricular tachycardia episodes. The arterial serum catechola mine levels (A, NA and DA), measured immediately after the stressor ap plication, were increased significicantly and were in negative correla tion with the arrhythmia parameters. Both changes were reversed by nal oxone (5 mg/kg) treatment after application of immobilization. The eff ects observed in this study may be attributed to the actions of endoge nous opioid peptides released during stress.