Teixeira A L, Fontoura B F, Freire-Maia L, Chiari E, Machado C R, Teixeira M M, Camargos E R
Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Auton Neurosci. 2001 Jun 20;89(1-2):128-32. doi: 10.1016/S1566-0702(01)00245-4.
Severe cardiac autonomic denervation occurs in the acute Chagas' disease in rats. The present study aims at verifying whether this denervation was accompanied by impairment of heart function. Scorpionic (Tityus serrulatus) crude venom was used for neurotransmitter release in isolated hearts (Langendorff's preparation). In control hearts, the venom induced significant bradycardia followed by tachycardia. In infected animals, despite the severe (sympathetic) or moderate (parasympathetic) cardiac denervation, the venom provoked similar bradycardia but the tachycardia was higher. The hearts of infected animals beat at significantly lower rate. Atropine prevented this lower rate. Our results demonstrated sympathetic dysfunction during the acute phase of Trypanosoma cruzi infection in rats, the parasympathetic function being spared.
