Intrarenal action of angiotensin II in restoring renal artery pressure after acute renal artery stenosis.

1. The renal artery of conscious dogs was acutely narrowed over 30 s to reduce renal artery pressure distal to the stenosis to 40 mmHg and the stenosis was maintained for 1 h. The distal renal artery pressure was rapidly restored to a plateau slightly below pre-stenosis values within 10--15 min. Rises in systemic blood pressure and plasma renin activity were small and transient. 2. This restoration was an active process, mediated by the intrarenal effects of angiotensin II (AII), since it was greatly diminished or abolished when the renal artery was narrowed in the presence of angiotensin I-converting enzyme inhibitor or angiotensin receptor antagonist (1-Sar-8-Ile AII). However, it was not diminished by 'total' autonomic effector blockade. 3. This angiotensin II-mediated restoration of renal artery pressure may be of homeostatic significance for the maintenance of glomerular filtration rate.