哺乳類の虹膜と網膜におけるメラノプシンシグナル伝達
1Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. txue77@gmail.com
Nature
|November 5, 2011
まとめ
哺乳類は脳とは無関係な内在の瞳孔光の反射 (PLR) を有しており,メラノプシンとPLCβ4.4が関与している. この経路は,本質的に光敏感な網膜のギャングリアン細胞の光反応に不可欠です.
科学分野:
- オフタルモロジック (眼科)
- 神経科学は神経科学である.
- 細胞生物学 細胞生物学
背景:
- 非哺乳類の脊椎動物は,本質的に光敏感な虹膜と瞳孔の光反射 (PLR) を表しています.
- 哺乳類のPLRは,目と脳の間のニューロン接続を必要とすると考えられています.
研究 の 目的:
- 哺乳類における内在的なPLRの存在とメカニズムを調査する.
- 哺乳類の内在的なPLRと網膜の光応答に関与する分子成分を解明する.
主な方法:
- ネズミの内在的なPLRを調査しました.
- PLCβ4.4の役割を評価するために,遺伝子ノックアウトモデル (Plcb4(-/-)) を利用しました.
- メラノプシン発現する内在的に光敏感な網膜のギャングリア細胞 (M1-ipRGCs) の光反応を調べました.
- TRPC6およびTRPC7発現を消去する効果を研究した.
主要な成果:
- PLRの固有の成分は,夜行性および夜間哺乳類に広く分布しています.
- マウスでは,この内在的なPLRはメラノプシンとPLCβ4.4に依存しています.
- Plcb4欠乏症は,本質的なPLRとM1-ipRGCsの光反応を排除しました.
- TRPC6とTRPC7は,固有のPLRには不可欠ではないが,M1-ipRGCの光反応に関与している.
- メラノプシンシグナル伝達経路は,虹膜と網膜の間に分岐する.
結論:
- 哺乳類は,虹膜のメラノプシンとPLCβ4によって媒介される内在的なPLRを持っています.
- PLCβ4依存経路は,内在的なPLRとM1-ipRGCの光感度の両方にとって重要である.
- メラノプシンシグナル伝達メカニズムは虹膜と網膜で動作する.
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