No evidence for vascular remodelling during hypertension induced by chronic inhibition of nitric oxide synthase in Brattleboro rats.
OBJECTIVE
To examine the effects of hypertension induced by chronic inhibition of nitric oxide synthase with NG-nitro-L-arginine methyl ester (L-NAME) on the structure of mesenteric resistance arteries.


METHODS
Brattleboro rats were given L-NAME (0.01-0.05 mg/ml, equivalent to 10-50 mg/kg per day) in their drinking water for 2-3 weeks. On the day of the experiment, mean arterial pressure was measured directly using an intra-arterial catheter that had been implanted 2 days previously. Isolated mesenteric resistance arteries were set up in a pressure-perfusion myograph in a calcium-free physiological solution and subsequently fixed with glutaraldehyde, embedded in Araldite, sectioned and examined histologically.


RESULTS
L-NAME administration increased mean arterial blood pressure in comparison with normotensive controls. No differences were found between the structural characteristics of mesenteric resistance arteries of first (pressurized diameter approximately 350 microns), second (approximately 270 microns) or third (approximately 200 microns) order vessels isolated from normotensive rats and rats that had been treated with L-NAME. There were no significant correlations between mean arterial blood pressure and the variables of internal diameter, media thickness and media: lumen area ratio.


CONCLUSIONS
Hypertension produced by chronic inhibition of nitric oxide synthase is not associated with remodelling of mesenteric resistance arteries in Brattleboro rats.
Dunn
W R
WR
Department of Physiology and Pharmacology, University of Nottingham Medical School, Queen's Medical Centre, UK.
Gardiner
S M
SM
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008638:Mesenteric Arteries / Q000503:physiopathology*; D009213:Myography; D019331:NG-Nitroarginine Methyl Ester; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D051381:Rats; D011910:Rats, Brattleboro; D013690:Television; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects
D001120:Arginine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester