视交叉上核调控睡眠觉醒行为的神经生物学机制

生物节律紊乱性睡眠障碍已成为日益严重的社会和医学问题，由于生物节律因素调节睡眠觉醒的机制不明，临床治疗缺乏有效对策。生物钟信号如何从节律中枢视交叉上核SCN传递到睡眠觉醒脑区，调控睡眠时相，成为睡眠研究领域关键科学问题。我们假说：SCN中不同类型神经元直接或间接向睡眠觉醒的神经核团投射，以神经肽或GABA为递（调）质，控制觉醒(或睡眠）的启动。本课题拟运用Cre动物、Cre依赖AAV病毒、光遗传学、药理遗传学、选择性神经元损毁、hrGFP追踪、电生理、Spike记录、免疫组化等方法，结合高度自动化睡眠解析平台，研究SCN中VIP、VP、CCK、SP、SCG2、GRP、CALB和CALR等神经元在睡眠觉醒调节中的作用，阐明SCN中调控睡眠觉醒的主要神经元类型、神经回路和神经递质等神经生物学机制。预期结果将丰富和发展睡眠觉醒调节理论，为发现治疗节律性睡眠障碍有效靶点提供新思路。

Circadian rhythm sleep disorders become severe social and medical problems. However, there are no effective ways to treat this insomnia clinically because the neural circuits and molecular mechanisms under which rhythm pace maker the suprachiasmatic nucleus (SCN) regulates sleep-wake cycle are not clear. We hypothesized that the signals of circadian rhythms were transmitted directly or indirectly from the SCN to the descending nuclei related to sleep-wake cycle to initialize or maintain sleep or wake stages. These neurons in the SCN may release GABA and/or neuropeptides. In the present study, we are going to use Cre mice for VIP，VP，CCK，SP，SCG2，GRP，CALB，CALR, and so on, AAV DIO Channelrhodopsin-2 (ChR2) or Halorhodopsin (NpHR)-mCherry, and designer receptors exclusively activited by a designer drug (DREADD) to control neuron activity specifically. This optogenetic technology allows targeted, fast control of precisely defined events in freely moving animals by delivering optical control at the speed (millisecond scale) and with the precision (cell type–specific) required for biological processing. By optogenetic approach of transfecting ChR2 or NpHR in different neurons in the SCN, automatic sleep bioassay systems, neuron spike recording, neurochemistry, and histochemistry approaches, we are going to clarify the key neurons in the SCN to initiate/maintain sleep or wake, neural circuits and molecular mechanisms involved. The outcome of the proposal will provide new insights into sleep-wake regulation by the key neurons in the SCN. This project will shed light on the neurobiological mechanisms for circadian rhythm sleep disorders, which in turn will aid in the development of novel treatment drugs.