Cardiac morphofunctional characteristics of transgenic rats with overexpression of the bradykinin B1 receptor in the endothelium


  • R.F. Levy
  • A.J. Serra
  • E.L. Antonio
  • L. dos Santos
  • D.S. Bocalini
  • J.B. Pesquero
  • M. Bader
  • V.F. Merino
  • H.A. de Oliveira
  • E.C. de Arruda Veiga
  • J.A. Silva
  • P.J.F. Tucci


  • Physiological Research


  • Physiol Res 66 (6): 925-932


  • OBJECTIVE: Evaluate whether endothelial overexpressing of the bradykinin B1 receptor could be associated with altered left ventricular and myocardial performance. METHODS: Echocardiography and hemodynamic were employed to assess left ventricular morphology and function in Sprague-Dawley transgenic rats overexpressing the endothelial bradykinin B1 receptor (Tie2B1 rats). The myocardial inotropism was evaluated on papillary muscles contradicting in vitro. RESULTS: In Tie2B1 animals, an enlarged left ventricular cavity and lower fractional shortening coupled with a lower rate of pressure change values indicated depressed left ventricular performance. Papillary muscle mechanics revealed that both Tie2B1 and wild-type rat groups had the same contractile capacities under basal conditions; however, in transgenic animals, there was accentuated inotropism due to post-pause potentiation. Following treatment with the Arg(9)-BK agonist, Tie2B1 papillary muscles displayed a reduction in myocardial inotropism. CONCLUSIONS: Endothelial B1 receptor overexpression has expanded the LV cavity and worsened its function. There was an exacerbated response of papillary muscle in vitro to a prolonged resting pause, and the use of a B1 receptor agonist impairs myocardial inotropism.