Cerebrovascular effects of [formula omitted] methylester are conserved under halothane anaesthesia

Abstract

The effects of the nitric oxide synthesis inhibitor N G - L-arginine methylester ( L-NAME) on mean arterial blood pressure (MABP) and local cerebral blood flow were determined in conscious and halothane-anaesthetised rats. Thirty minutes post-drug administration in conscious rats L-NAME (30 mg kg −1 i.v.) induced significant hypoperfusion (MABP 132±2 mmHg and 163±6mmHg (means ± S.D.) for saline and L-NAME groups respectively) and significant hypoperfusion throughout the brain (mean ± S.D. reduction in cerebral blood flow 27.3 ± 5.9% compared with controls). In contrast, under halothane anaesthesia, L-NAME did not significantly change MABP but significant reductions in cerebral blood flow (43.2 ± 3.7%) were observed. Thus the cerebrovascular response to L-NAME is conserved under halothane anaesthesia despite attenuation of the peripheral vasoconstrictive action.