EFFECT OF ANTIARRHYTHMICS ON THE RELEASE OF ADENOSINE IN RAT HEARTS WITH CORONARY-OCCLUSION AND REPERFUSION

In isolated perfused rat hearts the left coronary artery was occluded for 5 min, with subsequent reperfusion for 20 min. During the reperfus ion severe tachyarrhythmias were observed, with ventricular fibrillati on occurring in all hearts. Simultaneously, large amounts of adenosine and its degradation products inosine, hypoxanthine, xanthine and uric acid were released into the coronary perfusate. The antiarrhythmics q uinidine, lidocaine and gallopamil significantly decreased the release . The effect of quinidine and lidocaine was linked with the antifibril latory action of these drugs. Also the interruption of fibrillation im mediately after its appearance by potassium chloride decreased the rel ease of adenosine and its metabolites in a highly significant way. The effect of gallopamil on the release was independent of an antifibrill atory action. The findings indicate that different kinds of antiarrhyt hmic drugs can affect the release of nucleosides and oxypurines in hea rts with ischaemia and reperfusion.