Electrically induced tachyarrhythmia and the effect of propranolol on the release of cyclic AMP and prostaglandin E by the canine left ventricle.

In anesthetized open-chest dogs, tachyarrhythmia (TA) was electrically induced by above-threshold stimuli via the right ventricle. During TA, a significant increase in the release of PGE and cAMP was observed in the canine coronary sinus blood (CSB). The efflux of cAMP corresponded with a concomitant increase in the left ventricular tissue level of this nucleotide. Pretreatment with propranolol (1.0 mg/kg i.v.) prevented the TA-induced changes in the level of PGE as well as cAMP in the CSB and in the tissue levels of cAMP. There was an increase in the activity of phosphorylase a in the myocardial tissue during TA which could be abolished by propranolol pretreatment. These results suggest possible interrelationships among catecholamines, cAMP, and PGE.