title: Changes in the cardiac beta-adrenergic system provoked by different T. cruzi strains.
abstract: BACKGROUND
  It has been demonstrated that the beta-adrenergic signal transduction system is altered somewhere along its pathway in Trypanosoma cruzi infected hearts and we think that these alterations would differ according to the infection phase and the parasite strain. Their study would be important for the understanding of the disease's pathophysiology.
  
  
  METHODS
  In the present work we studied important components of this system in mice hearts infected with T. cruzi, Tulahuen strain and with SGO-Z12 isolate, obtained from a patient of an endemic area, in the acute phase of the infection, determining: the plasma catecholamines levels, the beta-receptors density and affinity as well as their function, the cardiac concentration of cAMP and the cardiac contractility as the physiologic response to the initial stimulus.
  
  
  RESULTS
  Plasma catecholamines levels were diminished in both infected groups when compared to the uninfected one (P < 0.01). The receptor's affinity was also diminished (P < 0.05) while their density was augmented only in the SGO-Z12 infected one (P < 0.01). The cAMP levels were higher in both infected groups (P < 0.01), the basal contractile force however increased only in the Tulahuen infected one (P < 0.01) while the response to catecholamines remained unchanged. The hearts infected with the SGO Z12 isolate presented an inferior response to epinephrine (P < 0.05) than the ventricles infected with the Tulahuen strain.
  
  
  CONCLUSIONS
  This model represents an important approach to understand the biochemical, physiological and molecular changes in the cardiac beta-adrenergic signalling that clearly begin in the acute phase of Chagas' disease and reveal a clear differentiation in the alterations produced by different parasite strains.
authors.affiliation: Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Santa Rosa 1085, 5000 Córdoba, Argentina.
authors.forename: M Silvina
authors.initials: MS
authors.lastname: Lo Presti
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Bustamante
authors.forename: Walter H
authors.initials: WH
authors.lastname: Rivarola
authors.forename: Alicia R
authors.initials: AR
authors.lastname: Fernández
authors.forename: Julio E
authors.initials: JE
authors.lastname: Enders
authors.forename: Ricardo
authors.initials: R
authors.lastname: Fretes
authors.forename: Gloria
authors.initials: G
authors.lastname: Levin
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Paglini-Oliva
mesh_terms: D000818:Animals; D002395:Catecholamines / Q000097:blood*; D002598:Chagas Cardiomyopathy / Q000097:blood*; D000242:Cyclic AMP / Q000032:analysis; D004837:Epinephrine / Q000097:blood*; D006321:Heart / Q000503:physiopathology; D006801:Humans; D051379:Mice; D009206:Myocardium / Q000737:chemistry; D009638:Norepinephrine / Q000097:blood*; D011943:Receptors, Adrenergic, beta / Q000032:analysis* / Q000502:physiology
chemical_list: D002395:Catecholamines; D011943:Receptors, Adrenergic, beta; D000242:Cyclic AMP; D009638:Norepinephrine; D004837:Epinephrine