Increase in gastric pH reduces hypotensive effect of oral sodium nitrite in rats


Autoria(s): Pinheiro, Lucas C.; Montenegro, Marcelo F.; Amaral, Jefferson H.; Ferreira, Graziele C.; Oliveira, Alisson M.; Tanus-Santos, Jose E.
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

01/11/2013

01/11/2013

2012

Resumo

The new pathway nitrate-nitrite-nitric oxide (NO) has emerged as a physiological alternative to the classical enzymatic pathway for NO formation from L-arginine. Nitrate is converted to nitrite by commensal bacteria in the oral cavity and the nitrite formed is then swallowed and reduced to NO under the acidic conditions of the stomach. In this study, we tested the hypothesis that increases in gastric pH caused by omeprazole could decrease the hypotensive effect of oral sodium nitrite. We assessed the effects of omeprazole treatment on the acute hypotensive effects produced by sodium nitrite in normotensive and L-NAME-hypertensive free-moving rats. In addition, we assessed the changes in gastric pH and plasma levels of nitrite, NOx (nitrate+ nitrite), and S-nitrosothiols caused by treatments. We found that the increases in gastric pH induced by omeprazole significantly reduced the hypotensive effects of sodium nitrite in both normotensive and L-NAME-hypertensive rats. This effect of omeprazole was associated with no significant differences in plasma nitrite, NOx, or S-nitrosothiol levels. Our results suggest that part of the hypotensive effects of oral sodium nitrite may be due to its conversion to NO in the acidified environment of the stomach. The increase in gastric pH induced by treatment with omeprazole blunts part of the beneficial cardiovascular effects of dietary nitrate and nitrite. (c) 2012 Elsevier Inc. All rights reserved.

Fundacao de Aparo a Pesquisa do Estado de Sao Paulo

Fundacao de Aparo a Pesquisa do Estado de Sao Paulo

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico

Coordenadoria de Aperfeicoamento de Pessoal de Nivel Superior

Coordenadoria de Aperfeicoamento de Pessoal de Nivel Superior

Identificador

FREE RADICAL BIOLOGY AND MEDICINE, NEW YORK, v. 53, n. 4, supl. 6, Part 1, pp. 701-709, AUG 15, 2012

0891-5849

http://www.producao.usp.br/handle/BDPI/37698

10.1016/j.freeradbiomed.2012.06.001

http://dx.doi.org/10.1016/j.freeradbiomed.2012.06.001

Idioma(s)

eng

Publicador

ELSEVIER SCIENCE INC

NEW YORK

Relação

FREE RADICAL BIOLOGY AND MEDICINE

Direitos

closedAccess

Copyright ELSEVIER SCIENCE INC

Palavras-Chave #NITRITE #OMEPRAZOLE #HYPERTENSION #L-NAME #FREE RADICALS #NO IN-VIVO #DIETARY NITRATE #BLOOD-PRESSURE #RENOVASCULAR HYPERTENSION #OXIDE METABOLITES #REDUCTION #HUMANS #BIOLOGY #DEOXYMYOGLOBIN #THERAPEUTICS #BIOCHEMISTRY & MOLECULAR BIOLOGY #ENDOCRINOLOGY & METABOLISM
Tipo

article

original article

publishedVersion