Species Differences in the Response of Mammalian Myocardial Fatty Acid Metabolism to Quinidine and Disopyraniide 1

Abstract

Summary

The effects of quinidine and disopyramide on oxygen consumption (Qo₂) and palmitate uptake by heart slices of rats, rabbits, and dogs were measured. The drugs did not diminish Qo₂ in three animal species studied with the exception of some depression seen at the highest concentration of quinidine in rat hearts. The disappearance of palmitate from the incubation medium was depressed by quinidine and disopyramide at higher concentrations in dogs. Similar depression but of a smaller magnitude was seen in rat myocardium at a lower drug concentration. Rabbit tissue, on the other hand, showed a marked increase in palmitate disappearance from the incubation medium when 1 × 10^-5 to 1 × 10^-4 M concentration of quinidine or disopyramide were tested.