Hierarchical self-organization of circadian system: synchronization of cellular oscillators and pacemaker coupling

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H04679
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental physiology(including physical medicine and nutritional physiology)
• Research Institution: Hokkaido University
• Principal Investigator: HONMA Sato 北海道大学, 脳科学研究教育センター, 招へい教員 (20142713)
• Co-Investigator(Kenkyū-buntansha): 榎木 亮介 北海道大学, 電子科学研究所, 准教授 (00528341) ; 小野 大輔 名古屋大学, 環境医学研究所, 助教 (30634224)
• Co-Investigator(Renkei-kenkyūsha): TOKUDA Isao 立命館大学, 理工学部, 教授 (00261389)
• Research Collaborator: MIEDA Michihiro ; OHMIYA Yoshihiro ; NAKAJIMA Yoshihiro ; KURODA Shigeru ; TAKAGI Seiji ; YOSHIKAWA Tomoko ; ODA Yoshiaki
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 生体リズム / 時計遺伝子 / 視交叉上核 / イメージング / 結合振動子

Outline of Final Research Achievements

We aimed to clarify the self-organizing mechanisms for the hierarchical multi-oscillator structure of the mammalian circadian clock in the suprachiasmatic nucleus (SCN) using knockout mice for clock genes and neuropeptides functions, luciferase reporter mice for continuous monitoring clock gene expression, and fluorescence sensors for monitoring intracellular calcium and membrane potentials. We demonstrated that both VIP and vasopressin act as synchronizers for cellular rhythms. We also found that their roles change depending on postnatal development, in which clock gene Cry is involved. We also found that GABA in the SCN acts not in cellular rhythm generation but in coherent neural rhythm output from the SCN to make the central circadian clock free of bursts. We further found that Per1 rhythms in the discrete areas in the SCN are involved in transferring photoperiodic signals to behavior rhythm output by changing the phase relations.

Free Research Field

環境生理学