ニューロンのライオノジン受容体は,日中時計の光による相遅延を媒介する
J M Ding1, G F Buchanan, S A Tischkau
1Department of Cell and Structural Biology, Neuroscience Program, University of Illinois, Urbana 61801, USA.
Nature
|August 5, 1998
まとめ
ライオノジン受容体は,細胞内カルシウムを放出することによって,昼間の時計の夜間遅延を媒介する. この発見は,夜間の光が哺乳類の生物リズムを環境とどのように同期させるかを明らかにしています.
科学分野:
- クロノバイオロジー クロノバイオロジー
- 神経科学は神経科学である.
- 分子生物学は分子生物学である.
背景:
- シルカディアンクロックは24時間の生物リズムを調節し,生物を環境と同期させます.
- 特に網膜のグルタマート信号を通し,上下神経核への夜間光の曝露は,日中時計の誘導の主要な調節因子である.
- グルタミン酸受容体の活性化により,カルシウムの流入が起こり,夜間の時間により,相変化効果 (遅延 vs 前進) が顕著になります.
研究 の 目的:
- 夜の早い時期に昼間の時計に光の相延ばし効果を及ぼす信号要素を特定する.
- この過程における細胞内カルシウム放出,特にライオノジン受容体経由の役割を調査する.
主な方法:
- 細胞内カルシウムチャネルライオノジン受容体と,結合カルシウムシグナル伝達におけるその役割の分析.
- 夜の早い時間に細胞内カルシウム貯蔵 (枯渇) の実験的操作.
- ライオノジン受容体の薬理学的活性化および抑制.
主要な成果:
- 夜早くに細胞内カルシウム貯蔵庫の枯渇は,グルタミン酸の相延ばし効果を廃止しました.
- ライアノジン受容体活性化剤は,夜明けにのみフェーズリセットを誘発した.
- ライオノジン受容体阻害剤は,光およびグルタミン酸誘発の相遅延を選択的に阻害しました.
結論:
- ライオノジン受容体を通じた細胞内カルシウム放出は,夜明けの光に対する日中時計の相遅延反応に不可欠である.
- このメカニズムは,特に夜間の光による昼間の時計のリセットの時間調節に寄与する.
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