ENERGETICS OF HEART-MITOCHONDRIA DURING ACUTE-PHASE OF TRYPANOSOMA-CRUZI INFECTION IN RATS

The energetics of heart mitochondria was studied in the acute phase of Trypanosoma cruzi infection in rats. Wistar rats were infected with 2 x 10(5) trypomastigote forms of the Y strain of T. cruzi, and heart m itochondria and submitochondrial particles isolated after 7 and 25 day s of infection. Ultrastructure of mitochondria seemed to be preserved, but cytochrome c levels were significantly depressed. Respiratory con trol ratios (RCR) were decreased for glutamate and succinate oxidation s, as a consequence of inhibition of respiration in state 3 and/or of stimulation of respiration in state 4. Stimulation of hydrolytic activ ity of FoF1-ATPase by energization of mitochondria was approx. 2-fold higher in relation to controls. Mitochondrial ATP concentration remain ed constant. In conclusion, during the acute phase of T. cruzi infecti on in rats there is an energy impairment at the level of heart mitocho ndria, but their ultrastructure and ATP concentration seem to be prese rved; the maintenance of ATP may be due to an adaptative mechanism of the cell which includes inhibition of the hydrolytic activity of FoF1- ATPase.