哺乳類の網膜の内在的な昼夜時計:視覚情報の網膜処理における重要性
Kai-Florian Storch1, Carlos Paz1, James Signorovitch2
1Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
Cell
|August 28, 2007
まとめ
Bmal1遺伝子が欠けているマウスは,網膜の光の反応が低下したことを示し,網膜の内部時計が視覚処理を調節することを示した. この研究は,眼機能における昼夜時計の重要性を強調しています.
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.
- オフタルモロジック (眼科)
背景:
- シルカディアンクロックはほとんどの哺乳類の組織に存在しますが,脳の上下神経核の外での役割はよく理解されていません.
- 網膜には固有の昼夜時計がありますが,視覚機能に対するその具体的な貢献は不明です.
研究 の 目的:
- 視覚処理の調節における内在の網膜の昼夜時計の役割を調査する.
- 光反応に関する網膜内のBmal1遺伝子の生理学的機能を決定する.
主な方法:
- すべての組織にBmal1遺伝子 (時計機能に不可欠) が欠けていた遺伝子組み換えマウスを利用した.
- 網膜に特異的なBmal1遺伝子の欠損を持つマウスを生成した.
- 光に対する網膜の転写反応,網膜内部の電気反応,光受容体の機能を評価した.
- 光と電子顕微鏡を用いて網膜の構造を評価した.
主要な成果:
- Bmal1が欠けていたマウスは,網膜の変異性トランスクリプション反応と,内部網膜の電気反応が光に欠陥を示した.
- 光に対する光受容体反応と網膜全体の構造は,これらのマウスでは正常のままでした.
- 網膜に特異的なBmal1の消去は,全身Bmal1ノックアウトマウスに似た視覚生理学的欠陥をもたらした.
- 光に対する網膜内部の電気反応における昼夜リズムは,網膜特異的なBmal1ノックアウトマウスには存在しなかった.
結論:
- 網膜内にある内在的な昼夜時計は,視覚処理の調節に重要な役割を果たします.
- Bmal1は,網膜の昼間時計の適切な機能と視力への影響に不可欠です.
- これらの発見は,網膜の昼間の時計と in vivo 視覚処理の間の直接的なリンクを確立しています.
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