Neuronal and homeostatic regulation of sleep by the preoptic area and tuberomammillary nucleus

项目摘要 虽然睡眠在所有被研究的动物中都是进化保守的，但睡眠的确切功能仍然存在。 未知生物体获得充足的睡眠是至关重要的，因为睡眠剥夺对生物体的健康有着深远的影响。 广泛的生理影响，包括认知障碍，免疫系统功能受损， 心血管疾病的风险增加，在极端情况下可能是致命的。在哺乳动物中， 其特征在于快速眼动（REM）和非REM（NREM）睡眠状态之间的过渡。睡眠 状态和它们之间的转换是由遍布大脑的不同神经元群调节的 并且受到体内平衡压力的影响。虽然大量的睡眠活跃和清醒活跃的大脑 虽然已经确定了不同的区域，但仍然不知道不同的神经元群体如何协调它们的行动， 调节睡眠和觉醒。下丘脑视前区（POA）含有睡眠活性物质， GABA能神经元及其轴突的激活是支配结节乳头核（TMN）的关键 睡眠调节。然而，目前还不清楚POA GABA能轴突的活性是如何被激活的。 对TMN的预测随着睡眠需求的增加而变化，以及它们是否有必要 整合稳态压力。相反，TMN组胺能神经元是唤醒活跃的，并支配TMN的神经元。 POA。TMN组胺能神经元或其他神经元的轴突投射的激活是如何被激活的尚不清楚。 POA的亚型促进觉醒。了解这些细胞类型的特定核如何协调作为一个 通过轴突投射的回路将有助于阐明睡眠和觉醒调节的机制。中央 该建议的假设是POA和TMN包含细胞类型特异性相互投射， 编码稳态睡眠需求并调节睡眠和觉醒。为了解决这一问题，该提案 将整合遗传小鼠模型，用于在体内和体外特异性标记特定细胞类型 使用纤维光度法、光极和全细胞膜片钳记录测量活性，以及 光遗传学和化学遗传学技术来调节神经元活性。目标1将研究POA的作用 睡眠稳态中GABA能轴突向TMN的投射。目标2将定义细胞类型的特定作用， 尾波调节中支配POA的TMN轴突总之，这些研究将揭示新的电路 POA和TMN在睡眠/清醒期间和睡眠/清醒期间协调其活动的机制 保持睡眠压力平衡

PROJECT SUMMARY While sleep is evolutionarily conserved across all animals studied, the precise function of sleep remains unknown. It is vital that organisms receive an adequate amount of sleep, as sleep deprivation has profound widespread physiological effects including cognitive impairment, compromised immune system function, increased risk of cardiovascular disease, and in extreme cases can be fatal. In mammals, sleep is characterized by transitions between rapid eye movement (REM) and non-REM (NREM) sleep states. Sleep states and transitions between them are regulated by diverse neuronal populations found throughout the brain and are under the influence of homeostatic pressure. While numerous sleep-active and wake-active brain regions have been identified, it remains unknown how diverse neuronal populations coordinate their actions to regulate sleep and wakefulness. The preoptic area (POA) of the hypothalamus contains sleep-active GABAergic neurons and activation of their axons innervating the tuberomammillary nucleus (TMN) are critical for sleep regulation. However, it is yet understood exactly how the activity of POA GABAergic axonal projections to the TMN changes in response to increased sleep need and whether they are necessary to integrate homeostatic pressure. Conversely, the TMN histaminergic neurons are wake-active and innervate the POA. It is unknown how the activation of axonal projections of TMN histaminergic neurons or other neuronal subtypes to the POA promotes wakefulness. Understanding how these cell-type specific nuclei coordinate as a circuit via axonal projections will help elucidate the mechanism of sleep and wake regulation. The central hypothesis of this proposal is that the POA and TMN contain cell-type specific reciprocal projections that encode homeostatic sleep need and mediate sleep and wakefulness. To address this hypothesis, this proposal will integrate genetic mouse models for specifically labeling specific cell types, in vivo and ex vivo measurements of activity using fiber photometry, optrode and whole-cell patch-clamp recordings, and optogenetic and chemogenetic techniques to modulate neuronal activity. Aim 1 will investigate the role of POA GABAergic axonal projections to the TMN in sleep homeostasis. Aim 2 will define cell-type specific roles of TMN axons innervating the POA in wake regulation. Together, these studies will reveal novel circuit mechanisms by which the POA and TMN coordinate their activity during sleep/wake and periods of homeostatic sleep pressure.