Elucidation of the physiological significance of zinc in taste cells

Research Project

Project/Area Number	18K06673
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 47030:Pharmaceutical hygiene and biochemistry-related
Research Institution	Setsunan University
Principal Investigator	NISHIDA Kentaro 摂南大学, 薬学部, 准教授 (20533805)
Co-Investigator(Kenkyū-buntansha)	長澤一樹京都薬科大学, 薬学部, 教授 (30228001) 大石晃弘京都薬科大学, 薬学部, 助教 (70780089)
Project Period (FY)	2018-04-01 – 2023-03-31
Project Status	Completed (Fiscal Year 2022)
Budget Amount *help	¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000) Fiscal Year 2021: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000) Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000) Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000) Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Keywords	微量元素 / 必須微量元素 / 味覚 / 味細胞 / 亜鉛
Outline of Final Research Achievements	In this study, zinc-positive signals in taste cells were showed by staining with a zinc fluorescence dye ZnAF-2DA in the rat circumvallate papillae. mRNAs for ZnT3 were expressed by isolated taste buds. ZnT3 immunoreactivity was found in type II and III taste cells, but not in type I cells. Moreover, we evaluated zinc release from isolated taste cells using a zinc-sensitive cells. Addition of taste mixture solution activated the zinc-sensitive cells with isolated taste cells. However, the percentage of response significantly decreased following pretreatment with MgEDTA as an extracellular zinc chelator, but not with ZnEDTA as a negative control. These findings suggest that zinc is released from taste cells into the intercellular area in response to taste stimuli, and zinc may affect signal transmission within taste buds.
Academic Significance and Societal Importance of the Research Achievements	味細胞から細胞間隙に放出される亜鉛は、味細胞の機能維持や味細胞から知覚神経終末へのシグナル伝達に何らかの影響を及ぼしている可能性が示唆された。本研究成果は、これまで考えられてきた味蕾における亜鉛が味細胞の分化・増殖に関わることのみならず、味細胞間及び味細胞-神経終末間に放出されることで、情報伝達機構において新たな生理的役割を担う可能性が考えられた。本研究は、味刺激により味細胞から亜鉛が放出されることを初めて示した研究成果であり、未だ不明な点が多く残されている味覚の情報伝達経路の解明の一助になると考えられた。