Post-ischemic release of nucleosides and oxypurines in isolated rat hearts. Possible involvement of ventricular fibrillation.

In isolated perfused rat hearts global ischemia for 2, 5, and 15 min was produced. Depending on the duration of the ischemia, postischemic reperfusion led to the release of adenosine and its catabolites, and to more or less severe ventricular tachyarrhythmias. When ventricular fibrillation occurred, a highly significant increase in the purine release was observed compared with non-fibrillating hearts. Prevention of fibrillation by antiarrhythmic drugs decreased the purine release in a highly significant way. After only 2 min of ischemia, reperfusion did not lead to ventricular fibrillation. Electrical induction of fibrillation during the reperfusion in these hearts provoked the release of very high amounts of the purine compounds. A similar effect of electrically-induced fibrillation was also obtained in hearts without a previous ischemic period. The findings suggest that ventricular fibrillation is able to induce the release of purine derivatives from the heart.