Premium
HAEMODYNAMIC RESPONSES TO N ‐NITRO‐l‐ARGININE IN CONSCIOUS RABBITS
Author(s) -
Du Z. Y.,
Dusting G. J.,
Woodman O. L.
Publication year - 1991
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1991.tb01466.x
Subject(s) - bradycardia , hexamethonium , vasoconstriction , vascular resistance , medicine , heart rate , anesthesia , hemodynamics , hindlimb , endocrinology , blood pressure , mean arterial pressure , atropine , reflex bradycardia
SUMMARY 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 = 33 ± 9 mmHg) and hindlimb vasoconstrictor action (ΔHVR = 0.4 ± 0.1 U) but did not affect HR (ΔHR = ‐ 1 ± 3 beats/min). 4. NOLA has a prolonged pressor and vasoconstrictor action which is independent of any action in the central nervous system and which results in a marked reflex bradycardia. These results suggest that the peripheral biosynthesis of nitric oxide is important in regulation vascular tone and arterial pressure.