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Expression of an angiotensin-(1-7)-producing fusion protein in rats induced marked changes in regional vascular resistance

Item Type:Article
Title:Expression of an angiotensin-(1-7)-producing fusion protein in rats induced marked changes in regional vascular resistance
Creators Name:Botelho-Santos, G.A. and Sampaio, W.O. and Reudelhuber, T.L. and Bader, M. and Campagnole-Santos, M.J. and Santos, R.A.
Abstract:We have described a transgenic rat line which express an Angiotensin-(1-7)-producing fusion protein, the TGR(A1-7)3292. In these rats testis acts as an angiotensin-(1-7) biological pump, increasing its plasma concentration 2.5 fold. In this study we performed hemodynamic measurements in TGR(A1-7)3292 and age-matched Hannover Sprague-Dawley (SD) control rats, using fluorescent microspheres. Urethane-anesthetized TG rats had similar level of baseline blood pressure (99 +/- 3 mmHg) as SD rats (101 +/- 3 mmHg). However, pronounced differences were observed in other hemodynamic measurements. TGR(A1-7)3292 rats presented a significantly increase in stroke volume (0.29 +/- 0.01 ml vs 0.25 +/- 0.01 ml in SD), increased cardiac index (24.6 +/- 0.91 ml/ min.Kg vs 21.9 +/- 0.65 ml/ min.Kg) and decreased total peripheral resistance (3.9 +/- 0.13 mmHg.ml (-1) .min.100g vs 4.5 +/- 0.13 mmHg.ml (-1) .min.100g). The increase in stroke volume in TGR may be partially explained by the small decrease in HR (326 +/- 7.0 beats/ min vs 359 +/- 6.0 beats/ min in SD). Strikingly, TGR(A1-7)3292 rats presented a substantial decrease in the vascular resistance in lung, spleen, kidney, adrenals, brain, testis and brown fat tissue with no significant differences in the left ventricle, mesentery, skin, gastrocnemius muscle and white fat tissue. These results corroborate and extend previous results observed after acute angiotensin-(1-7) infusion, showing that chronic increase in circulating angiotensin-(1-7) produces sustained and important changes in regional and systemic hemodynamics. Moreover our data suggest a physiological role for angiotensin-(1-7) in the tonic control of regional blood flow. Key words: hemodynamic, angiotensin-(1-7), fluorescent microspheres, transgenic rats.
Keywords:Angiotensin-(1-7), Hemodynamic, Blood flow, Fluorescent microspheres, Transgenic rats, Animals, Rats
Source:American Journal of Physiology Heart and Circulatory Physiology
ISSN:0363-6135
Publisher:American Physiological Society (U.S.A.)
Volume:292
Number:5
Page Range:H2485-H2490
Date:1 May 2007
Official Publication:https://doi.org/10.1152/ajpheart.01245.2006
PubMed:View item in PubMed

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