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Reduction of the nociceptive response to gastric distension by nitrate ingestion in rats
Author(s) -
Rouzade,
Anton Anton,
Fioramonti,
R. GarciaVillar,
Theodorou,
Buéno
Publication year - 1999
Publication title -
alimentary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.308
H-Index - 177
eISSN - 1365-2036
pISSN - 0269-2813
DOI - 10.1046/j.1365-2036.1999.00611.x
Subject(s) - nitric oxide , sodium nitroprusside , distension , gastric distension , ingestion , medicine , blood pressure , stomach , anesthesia , chemistry , endocrinology
Background : Dietary nitrates are known to produce nitric oxide in the stomach, which may influence gastric function. Aim : To investigate whether nitrate ingestion modifies gastric sensitivity to distension through a mechanism involving nitric oxide production. Methods : Nociception, associated with gastric distension ranging from 10 to 40 mmHg, was assessed in anaesthetized rats by the amplitude of cardiovascular depressor responses. Gastric volume corresponding to each distension was recorded. The following intragastric administrations (1 mL) were performed before distension: water (control), KNO 3 , NaNO 3 , KCl, NaCl (all at 0.1 mmol/kg), standard food (0.5 g), sodium nitroprusside, a nitric oxide donor (5 mg/kg), and haemoglobin, a nitric oxide scavenger (150 mg/kg) given either with water or KNO 3 . Results : In controls, the fall in blood pressure increased from 7.8 ± 2.0 to 31.6 ± 2.7 mmHg at distending pressures from 10 to 40 mmHg, respectively. KNO 3 significantly reduced the amplitude of blood pressure response for the highest distending pressures (35 and 40 mmHg), while KCl induced a reduction in blood pressure response at all gastric pressures. NaNO 3 and NaCl did not induce significant changes in distension‐induced depressor responses. Administration of 0.5 g of standard food or sodium nitroprusside reproduced the effect of KNO 3 , which was reversed by haemoglobin. None of the compounds modified the gastric pressure–volume relationship, except KNO 3 , which increased gastric volume for the lowest distending pressures, and haemoglobin, which reduced the volume for the highest pressure. Conclusions : Ingestion of potassium nitrate reduces the sensitivity to gastric distension, through a mechanism involving nitric oxide.