Laboratory of Physiology of Digestion, Pavlov Institute of Physiology of the Russian Academy of Sciences, St. Petersburg, Russia.
Digestion. 2011;83 Suppl 1:7-12. doi: 10.1159/000323398. Epub 2011 Mar 10.
Dietary-free L-glutamate (Glu) in the stomach interacts with specific Glu receptors (T1R1/T1R3 and mGluR1-8) expressed on surface epithelial and gastric gland cells. Furthermore, luminal Glu activates the vagal afferents in the stomach through the paracrine cascade including nitric oxide and serotonin (5-HT).
To elucidate the role of dietary Glu in neuroendocrine control of the gastrointestinal phase of gastric secretion.
In Pavlov or Heidenhain gastric pouch dogs, secretion was measured in the pouch while monosodium glutamate (MSG) was intubated into the main stomach alone or in combination with liquid diets.
In both experimental models, supplementation of the amino acid-rich diet with MSG (100 mmol/l) enhanced secretions of acid, pepsinogen and fluid, and elevated plasma gastrin-17. However, MSG did not affect secretion stimulated by the carbohydrate-rich diet and had no effect on basal secretion when applied in aqueous solution. Effects of MSG were abolished by denervation of the stomach and proximal small intestine with intragastrically applied lidocaine and partially suppressed with the 5-HT(3) receptor blocker granisetron.
Supplementation of amino acid-rich liquid diets with MSG enhances gastrointestinal phase secretion through neuroendocrine pathways which are partially mediated by 5-HT. Possible mechanisms are discussed.
胃中的膳食游离谷氨酸 (Glu) 与表面上皮细胞和胃腺细胞上表达的特定 Glu 受体（T1R1/T1R3 和 mGluR1-8）相互作用。此外，腔内 Glu 通过包括一氧化氮和 5-羟色胺（5-HT）的旁分泌级联激活胃中的迷走传入神经。
阐明膳食 Glu 在胃肠分泌的神经内分泌控制中的作用。
在 Pavlov 或 Heidenhain 胃囊犬中，在胃囊中测量分泌，同时将单谷氨酸钠 (MSG) 单独插入主胃或与液体饮食一起插入。
在这两种实验模型中，用 MSG（100mmol/l）补充富含氨基酸的饮食可增强酸、胃蛋白酶原和液体的分泌，并升高血浆胃泌素 17。然而，MSG 对富含碳水化合物的饮食刺激的分泌没有影响，并且当以水溶液形式应用时对基础分泌没有影响。MSG 的作用被胃和近端小肠的内源性麻醉和胃内应用利多卡因以及 5-HT（3）受体阻滞剂格兰司琼部分抑制而消除。
用 MSG 补充富含氨基酸的液体饮食可通过神经内分泌途径增强胃肠分泌期，其中部分途径由 5-HT 介导。讨论了可能的机制。
