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Improved cardiovascular autonomic modulation in transgenic rats expressing an Ang-(1-7)-producing fusion protein

Authors

  • D.R. Dartora
  • M.C. Irigoyen
  • K.R. Casali
  • I.C. Moraes-Silva
  • M. Bertagnolli
  • M. Bader
  • R. Santos

Journal

  • Canadian Journal of Physiology and Pharmacology

Citation

  • Can J Physiol Pharmacol 95 (9): 993-998

Abstract

  • Angiotensin-(1-7) counterbalances Angiotensin II cardiovascular effects. However, it has yet to be determined how cardiovascular autonomic modulation may be affected by chronic and acute elevation of Ang-(1-7). Hemodynamics and cardiovascular autonomic profile were evaluated in male Sprague-Dawley (SD) and transgenic rats (TGR) overexpressing Ang-(1-7) [TGR(A1-7)3292]. Blood pressure (BP) was directly measured while cardiovascular autonomic modulation was evaluated by spectral analysis. TGR received A-779 or vehicle and SD rats received Ang-(1-7) or vehicle and were monitored for 5 hours after i.v. administration. In another set of experiments with TGR, A-779 was infused for 7 days using osmotic mini pumps. Although at baseline no differences were observed, acute administration of A-779 in TGR produced a marked long lasting increase in BP accompannied by increased BP variability (BPV) and sympathetic modulation to the vessels. Likewise, chronic administration of A-779 with osmotic mini pumps in TGR increased heart rate, sympathovagal balance, BPV and sympathetic modulation to the vessels. Administration of Ang-(1-7) to SD rats increased HRV values in 88% accompannied by 8% of vagal modulation increase and 18% of mean BP reduction. These results show that both acute and chronic alteration in the Ang-(1-7)-Mas receptor axis may lead to important changes in the autonomic control of circulation, impacting either sympathetic and/or parasympathetic systems.


DOI

doi:10.1139/cjpp-2016-0557