Cardiac autonomic denervation and functional response to neurotoxins during acute experimental Chagas' disease in rats.
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.
Teixeira
A L
AL
Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Fontoura
B F
BF
Freire-Maia
L
L
Chiari
E
E
Machado
C R
CR
Teixeira
M M
MM
Camargos
E R
ER
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001919:Bradycardia / Q000139:chemically induced / Q000503:physiopathology; D002598:Chagas Cardiomyopathy / Q000503:physiopathology*; D003714:Denervation; D006321:Heart / Q000294:innervation* / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D008297:Male; D008790:Metoprolol / Q000494:pharmacology; D010275:Parasympathetic Nervous System / Q000503:physiopathology*; D010276:Parasympatholytics / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012604:Scorpion Venoms / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D013565:Sympatholytics / Q000494:pharmacology; D013610:Tachycardia / Q000139:chemically induced / Q000503:physiopathology; D014665:Vasodilator Agents / Q000494:pharmacology
D010276:Parasympatholytics; D012604:Scorpion Venoms; D013565:Sympatholytics; D014665:Vasodilator Agents; D001285:Atropine; D008790:Metoprolol; D000109:Acetylcholine