HAEMODYNAMIC RESPONSES TO N‐NITRO‐l‐ARGININE IN CONSCIOUS RABBITS

Abstract

1. The effect of N‐nitro‐l‐arginine (NOLA) on mean arterial pressure (AP), hindlimb vascular resistance (HVR) and heart rate (HR) was examined in conscious rabbits. 2. NOLA (15 mg/kg, i.v.) increased AP (ΔAP = 14 ± 3 mmHg) and HVR (ΔHVR = 0.8 ± 0.3 U) and decreased HR (ΔHR = ‐ 66 ± 8 beats/min). AP remained elevated for at least 2 h following NOLA infusion but had returned to control levels after 24 h. In contrast, the hindlimb vasoconstriction and bradycardia were sustained for at least 48 h but had returned to control levels after 72 h. 3. In the presence of total autonomic blockade (hexamethonium 30 mg/kg; propranolol 1 mg/kg and atropine 0.1 mg/kg) NOLA continued to have a pressor (ΔAP =..