Recovery from heart norepinephrine depletion in experimental Chagas' disease.

Norepinephrine (NE) was assayed fluorimetrically in the hearts of rats killed at different periods after inoculation with the Y strain of Trypanosoma cruzi. The levels of cardiac NE which, as reported previously, were not measurable 18, 22, and 32 days after inoculation became detectable at day 48. At day 70 these levels were around 50% of the control values and at day 97 normal values were attained in most animals. These results strongly suggest that sympathetic nerve fibers are destroyed in the acute phase of T. cruzi infection and regenerated during the chronic phase.