Abstract
We examined the effect of diltiazem on rat hearts using the Langendorff method. Perfusion was stopped during the ischemia to distinguish the effect of duration without the flow from that with reperfusion. Recovery of the myocardial function from ischemia/reperfusion in the control experiment was about 20% without recovery of the decreased ATP level in the myocardium. In contrast, diltiazem treatment prior to the ischemia led to recovery of the cardiac function after the reperfusion, although it had no effect on the reduction of the myocardial ATP level just after the ischemia; the ATP level recovered after the reperfusion. Diltiazem treatment also enhanced uric acid production in the reperfusion from the purine catabolites, which had been pooled in the myocardium during the ischemia. These results showed that uric acid production can occur in heart preparations and is not always related to the development of myocardial injury. We concluded that the protective effect of diltiazem on the cardiac function is not dependent upon the protection against ATP degradation in the myocardium during ischemia.
