title: Effects of ionic compositions of the medium on monosodium glutamate binding to taste epithelial cells.
abstract: Monosodium glutamate and nucleotides are umami taste substances in animals and have a synergistic effect on each other. We studied the ligand-binding properties of the glutamate receptors in taste epithelial cells isolated from bovine tongue. Specific glutamate binding was observed in an enriched suspension of taste receptor cells in Hanks' balanced salt solution, while no specific glutamate binding was apparent in the absence of divalent ions or when the cells had been depolarized by a high content of potassium in Hanks' balanced salt solution. There was no significant difference between the release of glutamate under depolarized or divalent ion-free conditions and under normal conditions. However, glutamate was easily released from the depolarized cells in the absence of divalent ions. These data suggest that the binding of glutamate to receptors depends on divalent ions, which also have an effect on maintaining binding between glutamate and receptors.
authors.affiliation: Research Institute for Food Science, Kyoto University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
authors.forename: T
authors.initials: T
authors.lastname: Tsunenari
authors.forename: T
authors.initials: T
authors.lastname: Mori
mesh_terms: D000818:Animals; D002412:Cations / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D003470:Culture Media; D004847:Epithelial Cells / Q000378:metabolism; D005503:Food Additives / Q000737:chemistry / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D008024:Ligands; D017470:Receptors, Glutamate / Q000378:metabolism*; D012970:Sodium Glutamate / Q000737:chemistry / Q000378:metabolism*; D013650:Taste Buds / Q000166:cytology / Q000378:metabolism*; D014059:Tongue / Q000378:metabolism
chemical_list: D002412:Cations; D003470:Culture Media; D005503:Food Additives; D008024:Ligands; D017470:Receptors, Glutamate; D018698:Glutamic Acid; D012970:Sodium Glutamate