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Diffusion of nitric oxide through the gastric wall upon reduction of nitrite by red wine: physiological impact.

Research paper by Bárbara S BS Rocha, Bruno B Gago, Rui M RM Barbosa, João J Laranjinha

Indexed on: 20 Jan '10Published on: 20 Jan '10Published in: Nitric Oxide



Abstract

In this work we showed that nitric oxide produced via red wine- and ascorbate-dependent reduction of nitrite diffuses through the rat stomach, inducing smooth muscle relaxation. The studies encompassed ex vivo and in vivo models of diffusion. Regarding the former, luminal *NO generated from a mixture of physiologic nitrite and ascorbate or wine diffuses across the stomach wall, being 8-20% of that produced in the mucosal side detected at high microM range (>100 microM) in the serosal side. In order to evaluate whether cellular dysfunction was associated with *NO diffusion at the microM range, the gastric tissue exposed to *NO was evaluated in terms of carbachol-induced muscle contraction in fundal strips and mitochondrial respiration and showed to remain functional and metabolically active. Moreover, pre-contracted gastric strips were shown to relax 86.5+/-5.5% (control) and 75.0+/-4.0% (nitrite/ascorbate-exposed tissue) when challenged with acidified nitrite. The studies in the living animal support the diffusion of luminal *NO to the gastric vasculature as, following addition of nitrite/ascorbate to rat stomach in vivo, *NO was not detected in the serosal environment but concentrations as high as 31 microM of *NO were detected outside the stomach after cardiac arrest. Collectively, the results establish a link between the consumption of nitrite and dietary reductants (e.g., wine polyphenols) and stomach muscle relaxation via the local chemical generation of *NO.