Zolotarev Vasiliy, Khropycheva Raisa, Uneyama Hisayuki, Torii Kunio
Pavlov Institute of Physiology of the Russian Academy of Sciences, Saint-Petersburg, Russia.
Ann N Y Acad Sci. 2009 Jul;1170:87-90. doi: 10.1111/j.1749-6632.2009.03900.x.
The amino acid, L-glutamate, which is abundant in many foodstuffs, is a potent stimulator of gastric vagal afferents. The aim of the study was to evaluate a role of dietary glutamate in neuroendocrine control of gastric secretion of acid, pepsinogen, and fluid. In mongrel dogs with small gastric pouches surgically prepared according to Pavlov (vagally innervated) or Heidenhain (vagally decentralized), secretion in a pouch was induced by infusion into the main stomach of an amino acid-rich diet lacking glutamate (Elental) or the same diet supplemented with monosodium glutamate (MSG). Having no effect alone, MSG (100 mM) potentiated secretion induced by Elental both in Pavlov and Heidenhain models. In the Pavlov pouch, the effect of MSG was markedly reduced after i.v. injection of granisetron, an antagonist of 5-HT(3) receptors. In the Heidenhain model, MSG enhanced the stimulatory effect of pentagastrin (1 microg/kg, s.c.). In conclusion, dietary glutamate at doses not exceeding its common concentrations in foods substantially potentiates gastric phase secretion induced by stimulation of gastric mucosa with an amino acid-rich diet or by administration of pentagastrin. The effect of glutamate is partially mediated via serotonin secretion and stimulation of 5-HT(3) receptors.
许多食物中都富含的氨基酸L-谷氨酸，是胃迷走神经传入纤维的强效刺激物。本研究的目的是评估膳食谷氨酸在胃酸、胃蛋白酶原和胃液分泌的神经内分泌控制中的作用。在按照巴甫洛夫法（迷走神经支配）或海登海因法（迷走神经离断）手术制备小胃囊的杂种犬中，通过向主胃灌注缺乏谷氨酸的富含氨基酸的饮食（伊伦塔尔饮食）或添加了味精（MSG）的相同饮食，诱导胃囊分泌。单独使用时无作用的味精（100 mM）在巴甫洛夫模型和海登海因模型中均增强了伊伦塔尔饮食诱导的分泌。在巴甫洛夫胃囊中，静脉注射5-HT(3)受体拮抗剂格拉司琼后，味精的作用明显减弱。在海登海因模型中，味精增强了五肽胃泌素（1微克/千克，皮下注射）的刺激作用。总之，剂量不超过其在食物中常见浓度的膳食谷氨酸，能显著增强由富含氨基酸的饮食刺激胃黏膜或给予五肽胃泌素诱导的胃期分泌。谷氨酸的作用部分是通过血清素分泌和5-HT(3)受体的刺激介导的。
