Mapping of cellular functions of taste-relaying neurons in the brain, defined by genetic tracing

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K09519
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 57010:Oral biological science-related
• Research Institution: Hiroshima University
• Principal Investigator: Sugita Makoto 広島大学, 医系科学研究科(歯), 教授 (50235884)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 味覚 / 情動 / 味覚誘発行動

Outline of Final Research Achievements

Taste information is transmitted to the gustatory cortex and the amygdala via synapses in the solitary tract nuclei and the parabrachial nuclei (PBN) to elicit behavioral and emotional responses. We combined genetic tracing with electrophysiological recordings and immunohistochemistry to functionally characterize bitter taste-relaying neurons in the PBN, the hypothalamus, and the amygdala, which were fluorescently labeled by the transneuronal tracer WGA-DsRed originating from T2R-expressing taste receptor cells. In the PBN, the WGA-DsRed-labeled neurons were located rostrally in the external lateral PBN, and caudally in the medial PBN. The tracer-labeled neurons in the medial and the external lateral PBN exhibited the different responsivities to neuromodulators in addition to different responses for integration of viscerosensory stimuli. The data indicate the differences in the neuron types and information processing between the neurons in the medial and external lateral PBN.

Free Research Field

口腔生理学

Academic Significance and Societal Importance of the Research Achievements

味覚経路を発生工学的トレーシングを用い標識することにより、初めて苦味経路ニューロンもしくは甘味経路ニューロンを可視化限定して、苦味もしくは甘味経路ニューロンのみの細胞機能を解析することができる。苦味・甘味経路ニューロンのニューロン種やシナプス伝達機構の解明を基にして、特定の苦味・甘味経路ニューロンに選択的に作用する薬剤を選出もしくは開発することが可能となる。それにより特定の苦味・甘味経路ニューロンを標的として、味覚異常、味覚識別障害、味覚誘発行動の異常、情動障害、拒食・過食への新しい治療法を創出する道を開く。