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Altered regional blood flow distribution in Mas-deficient mice

2012; SAGE Publishing; Volume: 6; Issue: 5 Linguagem: Inglês

10.1177/1753944712461164

1753-9455

Giancarla Aparecida Botelho-Santos, Michael Bäder, Nathalia Alenina, Robson A.S. Santos,

Hormonal Regulation and Hypertension

Background: We have recently shown that the acute infusion of angiotensin-(1–7) [Ang-(1-7)] or chronic increase in plasma Ang-(1-7) produces important changes in regional blood flow in rats. Methods: To further assess whether these changes are related to Mas, in this study hemodynamic measurements were performed in Ang-(1-7) receptor Mas knockout C57BL/6 (Mas-KO) mice and age-matched wild type (WT) control mice, using fluorescent microspheres. Results: Mean arterial pressure in urethane-anesthetized Mas-KO mice (12–16 weeks old) did not differ from that in WT mice (79 ± 2 and 80 ± 2 mmHg respectively). However, pronounced differences were observed in other hemodynamic measurements. Mas-KO mice exhibited a significant decrease in stroke volume (0.03 ± 0.01 versus 0.05 ± 0.01 ml/beat in WT) and decreased cardiac index (0.81 ± 0.08 versus 1.24 ± 0.24 ml/min/g in WT). Strikingly, Mas-KO mice exhibited a marked increase in vascular resistance and a decrease in blood flow in the kidney, lung, adrenal gland, mesentery, spleen and brown fat tissue. The decrease in blood flow ranged from 34% (spleen) to 55% (brown fat tissue). Conclusion: These results suggest that the Ang-(1-7)/Mas axis plays an important role in regional and systemic hemodynamic adjustments in mice.