Effect of verapamil on the transmural energy metabolism in the isoproterenol-induced myocardial lesion.

The effect of verapamil on the isoproterenol (ISO)-induced transmural metabolic lesion in the left ventricular wall was investigated in the rat heart. The treatment with ISO 2.5 mg/Kg s.c. on 2 consecutive days resulted in significant decreases of creatine phosphate in the subendocardium (ENDO) and of adenosine triphosphate in the ENDO and the subepicardium. On the other hand, inorganic phosphate (Pi) and lactate (LA) were increased in both layers. These changes were more prominent in the ENDO. Pretreatment with verapamil 25 mg/Kg s.c. prevented the reduction of high energy phosphate compounds and the increases of Pi and LA in both layers by ISO.