Angiotensin‐(1‐7) ICV Chronic Infusion Attenuates DOCA‐Salt Hypertension

Ang‐(1‐7)‐Mas receptor axis is an important counter‐regulator of Ang II‐AT 1 on cardiovascular actions. This study evaluated ICV chronic infusion of Ang‐(1‐7) on the progression of DOCA‐Salt hypertension. Sprague‐Dawley rats (3–4 months of age, 300–450g) were submitted to right cerebral ventricle cannulation (ICV), 7 days after deoxycorticosterone‐acetate (DOCA) implantation (200 mg/Kg, sc). ICV infusion was performed with ALZET osmotic pumps filled with Ang‐(1‐7) (200 ng/0.5 μl/h) or saline (0.5 μl/h; CTL) for 14 days. On the 14 th day of infusion, in conscious rats, baseline arterial pressure (AP), the sensitivity of the baroreflex bradycardia (BRS) and the cardiac autonomic tonus were evaluated. Ang‐(1‐7) ICV infusion reduced baseline mean AP (135 ± 8 mmHg vs 163 ± 3 mmHg, CTL), reduced baseline heart rate (325 ± 15 beats/min vs 383 ± 17 beats/min, CTL), increased the cardiac parasympathetic tonus (74 ± 4 beats/min vs 51 ± 8 beats/min, CTL), decreased the cardiac sympathetic tonus (57 ± 15 beats/min vs 101 ± 6 beats/min, CTL) and increased the BRS (1,49 ± 0,25 ms/mmHg vs 0,56 ± 0,10 ms/mmHg, CTL). These results suggest that increasing central Ang‐(1‐7) levels may contribute to the attenuation of arterial hypertension, at least in part, by altering the central integration of autonomic control of HR. Support Fapemig, CNPq, CAPES.