Neuronal counting and parasympathetic dysfunction in the hearts of chronically Trypanosoma cruzi - infected rats Contagem neuronal e disfunção cardíaca parassimpática em ratos cronicamente infectados pelo Trypanosoma cruzi

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: E. Chapadeiro, R.F.C. Florêncio, P.C. Afonso, P.S.S. Beraldo, P.C. de Jesus, L.F. Junqueira Jr.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 1991
• Subjects: Cardiac parasympathetic dysfunction; Experimental Chagas' disease; Neuroganglionitis; T. cruzi; Neuronal counting; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1590/S0036-46651991000500001; https://doaj.org/article/052169c913c94c079ad2fba2684364df

Ten male Wistar rats, chronically infected with Colombian, São Felipe (12SF) and Y strains of Trypanosoma cruzi and ten non-infected control animals were submitted to the bradycardia responsiveness test, an assessment of heart parasympathetic function, after phenylephrine injection. Six chagasic animals showed heart parasympathetic dysfuntion characterized by reduction in the index of bradycardia baroreflex responsiveness, as compared with the control group. Microscopic examination of the atrial heart ganglia of chagasic rats showed ganglionitis, but no statiscally significant reduction in the number of neurons. Dez ratos machos Wistar cronicamente infectados pelas cepas Colombiana, São Felipe (12SF), e Y do Trypanosoma cruzi, foram submetidos, após 8 meses de infecção, juntamente com dez animais controles, ao teste da resposta bradicárdica barorreflexa pela injeção endovenosa de fenilefrina. Seis ratos chagásicos exibiram disfunção cardíaca parassimpática, caracterizada pela depressão do índice da resposta bradicárdica barorreflexa. Embora o estudo histológico dos corações chagásicos mostrasse lesões dos gânglios atriais, a contagem dos neurônios em cortes seriados, não apresentou redução numérica significativa dos mesmos.