Elucidation of the mechanism of adaptation to light environment in SCN via orphan G protein-coupled receptors.

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K15572
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Environmental physiology(including physical medicine and nutritional physiology)
• Research Institution: Institute of Physical and Chemical Research (2020); Kyoto University (2017-2019)
• Principal Investigator: Murai Iori 国立研究開発法人理化学研究所, 生命機能科学研究センター, 客員研究員 (40792370)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 概日リズム / 光環境 / 視交叉上核 / 外側膝状体 / Vipr2

Outline of Final Research Achievements

Light is the most important external entrainment factor for the circadian clock in organisms, but the underlying process of integration of light information in the brain is unknown. In this study, we focused on the suprachiasmatic nucleus (SCN), the center of the biological clock, to elucidate the adaptation process of the circadian clock to the light environment via orphan G-protein-coupled receptors. We searched for G protein-coupled receptors whose functions in the suprachiasmatic nucleus are unknown, and found that calcitonin receptors are expressed in the suprachiasmatic nucleus and play a role in the diurnal variation of body temperature. We also found that Vipr2 receptor mRNA was strongly expressed in the lateral geniculate body, and Vipr2 expression in the lateral geniculate body on the side of retinal projection was reduced compared to the non-projecting side.

Free Research Field

神経科学

Academic Significance and Societal Importance of the Research Achievements

現代社会では夜間に大量の人工的な光を浴びる機会が多く、それが不眠症や精神疾患、高血圧症などの疾病につながる危険性が指摘されているが、脳内において光情報が統合され、外部環境に適応するプロセスは分かっていない。本研究成果はカルシトニン受容体の概日リズムへの新たな機能やVipr2を介した新たな脳内光情報処理回路の存在を示唆する知見で、概日時計の光環境への適応メカニズムの理解につながることが期待される。