Effects of central and peripheral angiotensin AT1 receptor antagonism on cardiac sympathetic nerve activity in conscious sheep

Abstract

Possible causes for the increased cardiac sympathetic nerve activity (CSNA) in heart failure (HF) are elevated circulating levels of angiotensin II (Ang II) and increased activity of central angiotensinergic mechanisms. We have, therefore, investigated the effects of blockade of the peripheral and central angiotensin systems on directly recorded CSNA in conscious normal sheep and sheep with pacing induced HF. Arterial pressure, CSNA and arterial baroreflex curves were measured prior to intravenous irbesartan (1 mg/kg/h) and after 90 minutes infusion. Similar measurements were made before and following central angiotensinergic blockade with intracerebroventricular (ICV) infusion of losartan (..