Lack of modulation of gastric emptying by dietary nitrate in healthy volunteers.
Nitric oxide produced endogenously in vagal neurons modulates gastrointestinal motor activity as an important non-adrenergic and non-cholinergic neurotransmitter. Other than through endogenous biosynthesis, a high concentration of nitric oxide also occurs by chemical reactions within the stomach in the presence of gastric acid through the entero-salivary re-circulation of dietary nitrate. Although dietary nitrate can be a potential source of nitric oxide in the human stomach, there has been no report on the effect of dietary nitrate on gastric motor function. The aim of this study is to investigate the effect of dietary nitrate on gastric emptying, one of the major parameters for the gastric motor function. Fifteen healthy volunteers underwent a placebo-controlled (310 mg sodium nitrate or placebo), double-blind, crossover trial. Since a sufficient amount of gastric acid is essential for dietary nitrate-derived nitric oxide generation in the stomach, the same protocol was repeated after 1-week treatment with a proton pump inhibitor, rabeprazole. Gastric emptying was evaluated by (13)C-octanoate breath test. The sodium nitrate ingestion did not affect gastric emptying either prior to or during rabeprazole treatment, although rabeprazole treatment itself significantly delayed gastric emptying, being independent of the dietary nitrate load. Confirmation of the delayed gastric emptying with rabeprazole indicates the sensitivity of the breath test employed in the present study. In conclusion, despite the potential nitrogen source of exogenous nitric oxide, the ingestion of 310 mg sodium nitrate, which is equivalent to the average daily intake of Japanese adults, does not affect gastric emptying in healthy volunteers.
Terai
Shiho
S
Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Japan.
Iijima
Katsunori
K
Asanuma
Kiyotaka
K
Ara
Nobuyuki
N
Uno
Kaname
K
Abe
Yasuhiko
Y
Koike
Tomoyuki
T
Imatani
Akira
A
Ohara
Shuichi
S
Shimosegawa
Tooru
T
D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000494:pharmacology; D000293:Adolescent; D000328:Adult; D000897:Anti-Ulcer Agents / Q000494:pharmacology; D001944:Breath Tests; D002210:Caprylates / Q000378:metabolism; D004032:Diet; D005746:Gastric Emptying / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D009566:Nitrates / Q000008:administration & dosage / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D064750:Rabeprazole; D012463:Saliva / Q000737:chemistry; D055815:Young Adult
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D002210:Caprylates; D009566:Nitrates; D009573:Nitrites; D064750:Rabeprazole; C031492:octanoic acid