BENEFICIAL-EFFECTS OF OXFENICINE ON THE HYPOXIC RAT ATRIA

During hypoxia the isolated rat atria released lactate into the bathin g medium and underwent a rise of resting tension and a decline of peak developed tension and pacemaker frequency. The atria from 24 h fasted rats, which oxidize faster their endogenous triacylglycerol pool, sho wed functional disturbances during hypoxia and a smaller recovery afte r reoxygenation than those from fed rats. Oxfenicine, which is a selec tive inhibitor of carnitine palmitoyltransferase I, attenuated the ris e of resting tension and improved the post-hypoxic recovery of peak te nsion in the atria from fasted rats. The decline of the pacemaker freq uency as well as the lactate output were not altered by the inhibitor. Present data show that oxfenicine ameliorated some of the hypoxic fun ctional disturbances. Inasmuch lactate output did not change and these effects manifested only in the atria predisposed to the utilization o f endogenous lipids, it may be inferred that oxfenicine preserved the atrial functions through the inhibition of fatty acid oxidation.