Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/194711
Type: Artigo de periódico
Title: Development Of Cardiomyocyte Hypotrophy In Rats Under Prolonged Treatment With A Low Dose Of A Nitric Oxide Synthesis Inhibitor.
Author: de Oliveira, C F
Cintra, K A
Teixeira, S A
De Luca, I M
Antunes, E
De Nucci, G
Abstract: Chronic administration of the nitric oxide (NO) synthesis inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) to rats causes hypertension and morphological abnormalities in the heart, consisting mainly of ventricular hypertrophy and foci of necrosis and fibrosis. Since these phenomena have usually been described with high (or moderate) doses of L-NAME, this study was undertaken to evaluate the effects of a low dose of L-NAME on arterial blood pressure, heart weight index, left ventricular weight index, amount of ventricular fibrosis, and cardiomyocyte size. Male Wistar rats received L-NAME (7.5 mg/kg per day) in the drinking water for 2, 4, and 6 months, whereas control animals received tap water alone. At this dose, L-NAME caused 90% inhibition (P<0.001) of brain NO synthase (NOS) activity. The chronic L-NAME treatment caused an approximately 15% reduction in body weight of the animals, and no death was observed. The tail-cuff pressure was markedly (P<0.01) elevated in L-NAME-treated rats. A significant (P<0.05) reduction in both heart weight index (13-20% decrease) and left ventricular weight index (20-34% decrease) at 2, 4, and 6 months of treatment was observed in L-NAME-treated rats. The cardiomyocyte size in subendocardial, subepicardial, and midmyocardial regions of the left ventricles was time-dependently reduced, irrespective of the region studied, as measured at 2 (11% decrease), 4 (28% decrease, P<0.05), and 6 (45% decrease, P<0.05) months of chronic L-NAME treatment. The amount of fibrous tissue was unaltered at 2 and 4 months, but a small (but significant) increase in the amount of fibrous tissue was detected at 6 months (7.1+/-0.2 %, P<0.05) compared to that of control animals (5.9+/-0.2%). Our results show that chronic treatment of rats with a low dose of L-NAME for prolonged periods (up to 6 months) causes arterial hypertension accompanied by significant reductions in heart weight, left ventricular weight indexes, and cardiomyocyte size.
Subject: Animals
Blood Pressure
Body Weight
Brain
Cardiomegaly
Enzyme Inhibitors
Fibrosis
Hypertrophy, Left Ventricular
Male
Myocardium
Ng-nitroarginine Methyl Ester
Nitric Oxide Synthase
Nitric Oxide Synthase Type I
Nitric Oxide Synthase Type Iii
Organ Size
Rats
Rats, Wistar
Rights: fechado
Identifier DOI: 
Address: http://www.ncbi.nlm.nih.gov/pubmed/10720643
Date Issue: 2000
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File SizeFormat 
pmed_10720643.pdf129.72 kBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.