Angiotensin‐(1‐7) infusion in the brain reduced blood pressure and cardiac hypertrophy in (mRen2)27 transgenic hypertensive rats (LB647)

Ang‐(1‐7) through Mas receptor is involved in the control of cardiovascular function and may present important cardioprotective actions after peripheral administration. In the present study, Sprague Dawley (SD) and transgenic hypertensive rats (mRen2)27, instrumented with telemetry probes for arterial pressure (AP) measurements, were subjected to 14 days of lateral ventricle (ICV) infusion of Ang‐(1‐7) (200 ng/h) alone, Ang‐(1‐7) (200 ng/h) in association with a Mas receptor antagonist (A779, 1 μg/h) or saline (0.5 µl/hour) through osmotic mini‐pumps. ICV Ang‐(1‐7) attenuated the hypertension of (mRen2)27rats and this effect was completely blocked by A779. The AP lowering effect of Ang‐(1‐7) was accompanied by a significant improvement of the baroreflex control of heart rate and an attenuation of the increased ratio of sympathetic/vagal activity to the heart of (mRen2). Further, there was a significant attenuation of the increased levels of atrial natriuretic peptide, brain natriuretic peptide, collagen I, fibronectin, TGF‐β1 and hypertrophy in the heart of (mRen2)27 rats. All effects induced by ICV Ang‐(1‐7) were reduced by the concomitant ICV infusion of A‐779. These data indicate that increased levels of Ang‐(1‐7) in the brain may contribute to the treatment of hypertension, not only by reducing the AP, but also leading to an attenuation of cardiac remodeling, at least in (mRen2) 27 hypertensive rats. These effects of Ang‐(1‐7) are likely to be mediated by Mas receptor interaction in the brain. Grant Funding Source : Supported by CAPES, FAPEMIG and CNPq through INCT NanoBioFar and PRONEX.