Trypanosoma cruzi: increased 5'-nucleotidase activity associated with dysfunction of adrenergic receptors in acutely infected albino Swiss mice

• Published in: The Journal of parasitology Vol. 85; no. 5; p. 970
• Main Authors: Fretes, R E, Paglini, P, Fernández, A R, Enders, J, de Fabro, S P
• Format: Journal Article
• Language: English
• Published: United States 01.10.1999
• Subjects: 5'-Nucleotidase - metabolism; Acute Disease; Adenosine - metabolism; Animals; Chagas Disease - enzymology; Chagas Disease - physiopathology; Densitometry; Heart Ventricles - enzymology; Heart Ventricles - ultrastructure; Immunohistochemistry; Mice; Microscopy, Electron; Myocardium - enzymology; Receptors, Adrenergic, beta - metabolism; Trypanosoma cruzi - enzymology
• ISSN: 0022-3395
• DOI: 10.2307/3285840

Adenosine, derived from hydrolysis of 5'-AMP by 5'-nucleotidase activity, may be involved in coupling coronary blood flow to cardiac function and metabolism; it has been postulated as a cardioprotective substance in ischemic myocardium. The stimulation of beta-adrenergic receptors produces an increase in adenosine by 5'-AMP hydrolysis. In addition, it has been demonstrated that in Chagas' disease there is decreased cardiac perfusion. We show in this paper by histochemical and densitometric procedures that ecto-5'-nucleotidase activity increases in ventricles of acutely Trypanosoma cruzi-infected mice and that the density of beta-adrenergic receptors is significantly diminished with affinity similar to controls, showing that a compensatory mechanism was absent. The increase of ecto-5'-nucleotidase in heart myocytes from infected mice may produce cardioprotective adenosine that may be independent of beta-adrenergic function, based on the hypoperfusion conditions of acute chagasic cardiomyopathy.