title: Numerical Evaluation of Efficacy of Glutamate on Gastrointestinal Motility: Rapid MRI Study.
abstract: The umami taste amino acid, glutamate acts as a signaling molecule in multiple cellular systems in the body, including the brain and gastrointestinal tract. Therefore, glutamate may affect appetite by modulating gastrointestinal motility as well as through taste perception. In this study, we examined the effect of glutamate on gastric emptying and duodenal motility, by using rapid magnetic resonance imaging (MRI). Ten healthy male volunteers participated in the measurements. Abdominal coronal MR images were successively acquired after ingestion of a liquid meal with and without monosodium L-glutamate (MSG). Image analysis was performed with a homemade segment software, in which respiratory motions were cancelled automatically by minimizing an energy function, thereby allowing participants breathe freely during MRI measurements. In two out of 10 participants, gastric emptying slowed down, while in the remaining eight participants, gastric residual volume decreased to 84% without MSG, and to 73% with MSG after 60 min. The inclusion of MSG enhanced duodenal motility, judging from changes in, 1) the magnitude of the duodenal area, 2) the center of gravity, and 3) the mean velocity of the wall motions. The third parameter most significantly indicated the excitatory effect of MSG on duodenum motility (3-7 fold increase). In conclusion, the present observations of rapid MRI indicate that MSG accelerates gastric emptying by facilitating duodenal motility, at least in healthy subjects with positive responses to MSG. This suggests the possible use of MSG as a prokinetic nutrient for improving the quality of life in hospitalized patients after a clinical assessment.
authors.affiliation: Department of Cell Physiology, Nagoya University Graduate School of Medicine.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Nakayama
authors.forename: Hidemi
authors.initials: H
authors.lastname: Teramoto
mesh_terms: D000818:Animals; D004386:Duodenum / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000502:physiology; D004734:Energy Metabolism / Q000187:drug effects; D005746:Gastric Emptying / Q000187:drug effects* / Q000502:physiology; D005769:Gastrointestinal Motility / Q000187:drug effects* / Q000502:physiology; D005971:Glutamates / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051381:Rats; D015398:Signal Transduction; D012970:Sodium Glutamate / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013270:Stomach / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000502:physiology; D013649:Taste / Q000187:drug effects* / Q000502:physiology*
chemical_list: D005971:Glutamates; D012970:Sodium Glutamate