The regulation mechanism of circadian oscillation in paraventricular nucleus and subparaventricular zone by the suprachiasmatic nucleus

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K06340
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44050:Animal physiological chemistry, physiology and behavioral biology-related
• Research Institution: Yamaguchi University
• Principal Investigator: Masumoto Kohei 山口大学, 大学院医学系研究科, 講師 (60580529)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 概日時計 / 視交叉上核 / 室傍核領域 / 神経連絡 / 軸索伸長 / GABA

Outline of Final Research Achievements

The center of the circadian clock is the suprachiasmatic nucleus (SCN) in the hypothalamus. To clarify how the SCN regulates the circadian oscillation of paraventricular nucleus (PVN) and subparaventricular zone (SPZ), we observed the coherence between the circadian rhythms in the SCN and PVN/SPZ by monitoring bioluminescence emitted using the brain tissue slice from Per2::luc knock-in mice. We revealed that GABA affected the circadian oscillations in the SCN and PVN/SPZ, and that Cl- transporter modulated the phase difference of circadian oscillations in the SCN and PVN/SPZ. In addition, GABA was expressed in the cultured brain slices in which circadian oscillations were restored. The Cl- transporter was expressed in the SCN at subjective night. In the future, we will reveal the relationship between intracellular Cl- concentration, GABA excitability/inhibition and circadian oscillation at in vivo mice.

Free Research Field

脳神経科学

Academic Significance and Societal Importance of the Research Achievements

体内時計の中枢である視交叉上核が刻む概日振動が、どのように他の脳領域に伝わり、どのように概日振動を制御しているか明らかにされていない。隣接領域である視交叉上核と室傍核領域間の時刻情報伝達機構を解明することは、この問題を解明するために必須である。
夜行性・昼行性動物の視交叉上核における概日振動の位相は同じであるが、視交叉上核外の概日振動の位相は昼行性・夜行性動物で逆転する。また、GABA受容体の興奮性・抑制性は細胞内Cl-濃度により変化する。生体マウスにおいて細胞内Cl-濃度とGABAの興奮性・抑制性、概日振動の関係を明らかにすることは、昼行性・夜行性の切り替えの解明に繋がると期待できる。