嗅覚受容体ニューロンの匂い物質に対する基本的な反応
Vikas Bhandawat1, Johannes Reisert, King-Wai Yau
1Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. vbhanda@mail.jhmi.edu
まとめ
嗅覚信号の増幅は,嗅覚受容体が短期間リガンドを結合し,数少ないGタンパク質分子を活性化するため,最小限です. これは,ロドプシンが信号を大きく増幅する網膜の光受容体と対照的です.
科学分野:
- 分子生物学は分子生物学である.
- セルラー・シグナリング
- 神経科学は神経科学である.
背景:
- ヘテロトリメリックGタンパク質のシグナル伝達は,細胞機能にとって極めて重要です.
- 膜受容体による信号増幅,特に受容体ごとに活性化されるGタンパク質の数は,細胞応答の重要な決定因子であるが,しばしば不明である.
- 網膜の棒細胞における光伝導は,一つの活性化されたロドプシン分子が多数のトランスデューシンGタンパク質を活性化することで,著しい増幅を示します.
研究 の 目的:
- 嗅覚伝導における信号増幅の範囲を調査する.
- 単一の嗅覚受容体によって活性化されたGタンパク質分子の数を決定する.
- 嗅覚と光伝導における増幅メカニズムを比較する.
主な方法:
- 嗅覚受容体活性化とその後のGタンパク質結合の分析.
- 嗅覚信号伝達経路における基本的な応答の測定.
- 嗅覚カスケードと光伝導カスケードの運動パラメータの比較.
主要な成果:
- 嗅覚伝導における基本的な応答は,例外的に小さい.
- リンガンド結合のオドラント受容体は,単一のGタンパク質分子さえも活性化する可能性が低い.
- これは,嗅覚物質が受容体に留まる時間が非常に短いことによるものです.
結論:
- 嗅覚伝導における信号増幅は,根本的に異なるもので,光伝導よりもはるかに効率が悪い.
- 短時間のオロラント受容体相互作用は,嗅覚における増幅の可能性を制限する.
- これらの違いを理解することは,感覚信号処理の理解の鍵です.
さらに関連する動画
10:16Perforated Patch-clamp Recording of Mouse Olfactory Sensory Neurons in Intact Neuroepithelium: Functional Analysis of Neurons Expressing an Identified Odorant Receptor
Published on: July 13, 2015
09:53Real-time In Vitro Monitoring of Odorant Receptor Activation by an Odorant in the Vapor Phase
Published on: April 23, 2019
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