The Tuberal Hypothalamus and Arousal State Control

下丘脑结节和觉醒状态控制

• 批准号: 9751986
• 负责人: Thomas S Kilduff
• 金额: $ 65.93万
• 依托单位: SRI INTERNATIONAL
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-30 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9751986
• 关键词: Ablation; Affect; Amygdaloid structure; Anatomy; Animal Model; Animals; Area; Arousal; Brain; Brain region; Cataplexy; Cell Nucleus; Cells; Chronic; Complement; Diet; Dorsal; Doxycycline; Eating; Electrophysiology (science); Energy Metabolism; Excision; Fluorescence; Food Energy; Functional Imaging; Head; Human; Hypothalamic structure; Image; Investigation; Knockout Mice; Ligands; Measures; Medial; Metabolism; Modeling; Mus; Narcolepsy; Neurodegenerative Disorders; Neurons; Peptides; Pharmacogenetics; Phenotype; Physiological; Population; REM Sleep; Rabies; Reporting; Role; Sleep; Sleep Disorders; Sleep Wake Cycle; Sleeplessness; System; Testing; Wakefulness; base; cell type; cholinergic neuron; clinically relevant; experimental study; follow-up; hypocretin; imaging study; locus ceruleus structure; mammilloinfundibular nucleus structure; melanin-concentrating hormone; melanin-concentrating hormone receptor; mouse model; nerve supply; optogenetics; patch clamp; restoration; sleep regulation

Melanin-concentrating hormone (MCH) and hypocretin/orexin (HCRT)-expressing neurons are intermingled populations in the tuberal hypothalamus that project widely throughout the brain to many of the same terminal fields. Whereas the HCRT system has been implicated in the control of wakefulness because the sleep disorder narcolepsy results when these cells degenerate, this system is also involved in energy metabolism. Conversely, the MCH system has primarily been associated with food intake and energy metabolism, but recent studies have established that MCH neurons also participate in the regulation of sleep and wakefulness. The hypothesis underlying this proposal is that the HCRT system is wake-stabilizing and REM-inhibiting whereas the MCH system is sleep-facilitating and REM-stabilizing. We will test this hypothesis by determining the phenotype of mice in which either the HCRT or MCH neurons have been partially ablated by removal of doxycycline in the diet of two conditional mouse models. We will then evaluate whether partial ablation of the HCRT neurons results in a phenotype of narcolepsy without cataplexy and whether cataplexy is exacerbated by simultaneously eliminating both neuronal populations. We will also assess whether direct connectivity exists between these cell groups using optogenetically-assisted neuroanatomical tracing and whole-cell patch- clamp electrophysiology in the presence and absence of selective HCRT and MCH receptor antagonists. To assess what occurs in the brain when the HCRT neurons degenerate as in human narcolepsy, we will use the conditional HCRT neuron ablation model to determine how the excitability of the MCH population is affected by chronic loss of HCRT input. We will also use conditional MCH neuron ablation to assess the converse effect of MCH loss on HCRT neuron excitability. Based on recordings from a limited number of cells in head-fixed animals, the HCRT and MCH neurons have been reported to have reciprocal activity across the sleep-wake cycle with HCRT neurons having their highest firing rates during active wakefulness and MCH neurons being primarily active during REM sleep. To determine the accuracy of this conclusion, we will use genetically- encoded Ca2+ indicators and microendoscopic imaging to measure the activity of hundreds of HCRT and MCH neurons across the sleep/wake cycle in unrestrained, freely-moving animals. To evaluate whether the HCRT and MCH neurons are functionally interconnected, we will pharmacogenetically activate one population while imaging Ca2+ fluorescence in the other population in the presence of selective HCRT and MCH receptor antagonists. Lastly, since these two populations project to many of the same brain regions, we will assess their relative input to brain areas known to be involved in arousal state control, specifically, the locus coeruleus, tuberomammillary nucleus, medial septum, and the amygdala. Together, these experiments should provide a more complete picture of the anatomical and functional connectivity of these two populations and the consequences of selective loss of one population or the other.

黑色素浓缩激素（MCH）和表达神经元的低载素/Orexin/Orexin（HCRT） 结节下丘脑中的种群，该山丘脑广泛投射到整个大脑的许多终端 字段。而HCRT系统与觉醒的控制有关，因为睡眠 当这些细胞退化时，发作性发育不全时，该系统也参与了能量代谢。 相反，MCH系统主要与食物摄入和能量代谢有关，但 最近的研究表明，MCH神经元也参与了睡眠和清醒的调节。 该提案的基础假设是HCRT系统正在唤醒和抑制 而MCH系统则在睡眠和刺激性。我们将通过确定 HCRT或MCH神经元通过去除部分消融的小鼠表型 两种条件小鼠模型的饮食中的强力霉素。然后，我们将评估是否部分消融 HCRT神经元导致发作性发作的表型，而无需瘫痪，并且是否急切地恶化 通过同时消除两个神经元种群。我们还将评估直接连接是否 使用光遗传辅助神经解剖学和全细胞斑块之间存在这些细胞组之间的存在 在存在和不存在选择性HCRT和MCH受体拮抗剂的情况下，夹紧电生理学。到 评估当HCRT神经元与人类性疾病中的HCRT神经元变性时，大脑中发生的情况，我们将使用 有条件的HCRT神经元消融模型，以确定MCH种群的兴奋性如何受到 HCRT输入的慢性损失。我们还将使用条件MCH神经元消融来评估 HCRT神经元兴奋性的MCH损失。基于头部固定数量有限的单元的记录 据报道，动物，HCRT和MCH神经元在整个睡眠中具有相互活性 HCRT神经元的循环在主动清醒期间发射速率最高，而MCH神经元为 主要在REM睡眠期间活跃。为了确定该结论的准确性，我们将在遗传上使用 编码的CA2+指标和微观镜面成像，以测量数百种HCRT和MCH的活性 在不受约束的自由移动动物中，神经元在睡眠/唤醒周期中。评估HCRT是否 MCH神经元在功能上相互联系，我们将在药物遗传学上激活一个人群，而 在选择性HCRT和MCH受体的存在下，其他人群的成像Ca2+荧光成像 对手。最后，由于这两个人口向许多相同的大脑区域项目，我们将评估 它们对已知参与唤醒状态控制的大脑区域的相对输入，具体是基因座二氧化碳， 结核肌核，内侧隔膜和杏仁核。这些实验应该一起提供 这两个人群的解剖学和功能连接的更完整的图片以及 选择性损失一个人群或另一个人口的后果。