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Updated: Jun 20, 2026

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Calcium Imaging of Odor-evoked Responses in the Drosophila Antennal Lobe
Published on: March 14, 2012
ドロソフィラの嗅覚受容体は,リガンドゲートおよびサイクルヌクレオチド活性化カチオンチャネルの両方である
Dieter Wicher1, Ronny Schäfer, René Bauernfeind
1Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-St 8, D-07745 Jena, Germany. dwicher@ice.mpg.de
Nature
|April 15, 2008
まとめ
昆虫の嗅覚受容体は,Gタンパク質結合受容体 (GPCR) だけでなく,リガンドゲートイオンチャネルとして機能します. この二重メカニズムは,昆虫における快速かつ長期にわたる匂いのシグナル伝達を可能にします.
科学分野:
- 嗅覚受容体のメカニズム
- 昆虫のケモセンセーション
- Gタンパク質結合受容体 (GPCR) 信号伝達
背景:
- 嗅覚信号は,通常,cAMPの生成を開始し,嗅覚ニューロン内のイオンチャネルを活性化するGタンパク質結合受容体 (GPCR) によって知覚されます.
- 昆虫の嗅覚受容体 (ORs) は,GPCRとシーケンスの類似性がなく,従属タンパク質 (例えば,Or83b) との二重体として機能し,従来のモデルに異議を唱える.
- 差異にもかかわらず,昆虫の嗅覚ニューロンはGタンパク質とcAMP経路の成分を発現し,嗅覚知覚の役割を示唆しています.
研究 の 目的:
- シャペロン Or83b.と共発する昆虫の嗅覚受容体 (ORs) の信号伝達機構を調査する.
- 昆虫のORがリガンドゲートイオンチャネルとして機能するかどうかを判断し,周期性核酸との相互作用を探求する.
主な方法:
- 哺乳類の細胞における昆虫の嗅覚受容体 (Or22a) とチャペロンタンパク質 (Or83b) の共発.
- 臭味剤の適用時にイオン電流を測定するための電気生理学的記録.
- 細胞内カルシウム (Ca2+) 濃度の変化の評価.
- サイクルアデノシンモノフォスファート (cAMP) とサイクルグアナシンモノフォスファート (cGMP) によってOr83bチャネル活性化の調査.
主要な成果:
- Or22aとOr83bの共同発現は,イオノトロプ的経路とメタボトロプ的経路の両方を通して,オドラントによって活性化された非選択的カチオン電流をもたらしました.
- 匂い刺激により,細胞内Ca2+濃度が上昇した.
- Or83bは,香料とは関係なく,細胞内cAMPまたはcGMPによって直接活性化される機能的なイオンチャネルを形成します.
結論:
- 昆虫の嗅覚受容体は,リガンドゲートイオンチャネルとして機能し,周期性ヌクレオチドで活性化されたチャネルとの複合体を形成します.
- この二重メカニズムは,昆虫における迅速で一時的な,そして敏感で長期にわたる匂いのシグナリングの両方を可能にします.
- 発見は,カノニカルGPCR経路とは異なる嗅覚信号伝導の新しいモードを明らかにしています.
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