Angiotensin IV Reverses the Acute Cerebral Blood Flow Reduction after Experimental Subarachnoid Hemorrhage in the Rat

Abstract

The effect of angiotensin (ANG) IV on CBF after experimental subarachnoid hemorrhage (SAH) was studied in rats using laser-Doppler flowmetry. ANG IV (1 microgram/kg/min i.v.) or saline treatments were started 20 min after SAH. ANG IV increased CBF (from 45 to 84% of baseline) by 60 min. In the saline group, CBF remained low (51%). Pretreatment with the specific ANG II antagonist Sar1, Ile8-ANG II did not antagonize ANG IV. Determination of nitric oxide synthase (NOS) activity in vitro or inhibition of NOS in vivo did not support a role for NO in the action of ANG IV.