B. Rocha, Bruno Gago, R. Barbosa
May 1, 2015
Citations
1
Influential Citations
15
Citations
Quality indicators
Journal
Free radical biology & medicine
Abstract
BACKGROUND Nitric oxide ((∙)NO), a ubiquitous molecule involved in a plethora of signaling pathways, is produced from dietary nitrate in the gut through the so-called nitrate-nitrite-NO pathway. In the stomach, nitrite derived from dietary nitrate triggers a network of chemical reactions targeting endogenous and exogenous biomolecules, thereby producing new compounds with physiological activity. OBJECTIVE The aim of this study was to ascertain whether compounds with physiological relevance are produced in the stomach upon consumption of nitrate- and ethanol-rich foods. DESIGN Human volunteers consumed a serving of lettuce (source of nitrate) and alcoholic beverages (source of ethanol). After 15 min, samples of the gastric headspace were collected and ethyl nitrite was identified by GC-MS. Wistar rats were used to study the impact of ethyl nitrite on gastric smooth muscle relaxation at physiological pH. RESULT Nitrogen oxides, produced from nitrite in the stomach, induce nitrosation of ethanol from alcoholic beverages in the human stomach yielding ethyl nitrite. Ethyl nitrite, a potent vasodilator, is produced in vivo upon the consumption of lettuce with either red wine or whisky. Moreover, at physiological pH, ethyl nitrite induces gastric smooth muscle relaxation through a cGMP-dependent pathway. Overall, these results suggest that ethyl nitrite is produced in the gastric lumen and releases (∙)NO at physiological pH, which ultimately may have an impact on gastric motility. Systemic effects may also be expected if ethyl nitrite diffuses through the gastric mucosa reaching blood vessels, therefore operating as a (∙)NO carrier throughout the body. CONCLUSION These data pinpoint posttranslational modifications as an underappreciated mechanism for the production of novel molecules with physiological impact locally in the gut and highlight the notion that diet may fuel compounds with the potential to modulate gastrointestinal welfare.