title: Characterization of umami receptor and coupling G protein in mouse taste cells.
abstract: Taste receptor cells (TRCs) express multiple umami receptors. We performed physiological investigations to determine whether umami-responding cells in taste buds possess G protein-coupled receptors and to determine what type of G proteins exist if any. To clarify the components that participate in intracellular umami signal transduction in mouse, we recorded the activation of TRCs. TRCs treated with the G protein inhibitor GDP-beta-S lost umami-induced inward currents. Treatment with the Galphai inhibitor, pertussis toxin, did not increase the intracellular Ca2+ level in many TRCs. Immunohistochemical analysis revealed that a subset of TRCs responding to umami stimuli expressed alpha-gustducin. Thus, we demonstrated that umami stimuli were received by G protein-coupled receptors that function together with some of the Galphai family members.
authors.affiliation: Graduate School of Agriculture, Kyoto University, Uji, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Narukawa
authors.forename: Keiko
authors.initials: K
authors.lastname: Kitagawa-Iseki
authors.forename: Hideaki
authors.initials: H
authors.lastname: Oike
authors.forename: Keiko
authors.initials: K
authors.lastname: Abe
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Mori
authors.forename: Yukako
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D004594:Electrophysiology; D005260:Female; D044385:GTP-Binding Protein alpha Subunits / Q000502:physiology; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000502:physiology; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D020962:Heterotrimeric GTP-Binding Proteins / Q000032:analysis / Q000502:physiology; D007120:Immunochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D018408:Patch-Clamp Techniques; D037342:Pertussis Toxin / Q000494:pharmacology; D043562:Receptors, G-Protein-Coupled / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013649:Taste / Q000502:physiology; D013650:Taste Buds / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology
chemical_list: D044385:GTP-Binding Protein alpha Subunits; D043562:Receptors, G-Protein-Coupled; D013873:Thionucleotides; C431926:taste receptors, type 1; D006153:Guanosine Diphosphate; C023427:guanosine 5'-O-(2-thiodiphosphate); D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; C524407:GNAT3 protein, mouse; D020962:Heterotrimeric GTP-Binding Proteins; D002118:Calcium