Trypanosoma cruzi: increased 5'-nucleotidase activity associated with dysfunction of adrenergic receptors in acutely infected albino Swiss mice.
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.
Fretes
R E
RE
Fac Cs Médicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Argentina.
Paglini
P
P
Fernández
A R
AR
Enders
J
J
de Fabro
S P
SP
D015720:5'-Nucleotidase / Q000378:metabolism*; D000208:Acute Disease; D000241:Adenosine / Q000378:metabolism; D000818:Animals; D014355:Chagas Disease / Q000201:enzymology / Q000503:physiopathology*; D003720:Densitometry; D006352:Heart Ventricles / Q000201:enzymology / Q000648:ultrastructure; D007150:Immunohistochemistry; D051379:Mice; D008854:Microscopy, Electron; D009206:Myocardium / Q000201:enzymology; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000201:enzymology*
D011943:Receptors, Adrenergic, beta; D015720:5'-Nucleotidase; D000241:Adenosine