Contributions of Astroglial Calcium Activity to Sleep Homeostasis

项目摘要 根据疾病控制和预防中心，睡眠不足是一种流行病， 具有重大的临床和经济影响。睡眠不佳可能是由睡眠稳态受损引起的， 调节睡眠需求作为先前清醒的函数。因此，确定睡眠的细胞基础 内稳态对于了解睡眠异常的根本原因是必要的。睡眠的生物学基础 内环境稳定还不完全清楚，但胶质星形胶质细胞可能起中心作用。发现星形胶质细胞 并调节对睡眠不足的补偿反应。因为星形胶质细胞的化学信号 是由细胞内钙的变化介导的，我假设星形胶质细胞内钙动力学 有助于睡眠需求的积累和释放。我将从两个方面来检验这个假设：1）描述 自发睡眠和对睡眠剥夺的反应中星形胶质细胞钙动力学; 2）确定 星形胶质细胞钙信号对睡眠稳态的影响。星形胶质细胞胞内钙离子活性 细胞体和突起将在体内用头戴式落射荧光显微镜和双光子 在选择性表达遗传编码的钙指示剂GCaMP 6 f的未麻醉小鼠中进行显微镜检查 在星形胶质细胞中。星形胶质细胞钙动力学将与睡眠-觉醒行为同时记录， 在生理条件下，由脑电图和肌电图确定， 睡眠剥夺，以及随后的星形胶质细胞内钙储存的遗传耗竭。这些研究报告将 第一个描述星形胶质细胞钙活性与脑电图测定 唤醒状态这些实验的结果将为星形胶质细胞介导提供新的机制性见解 睡眠平衡的关键

PROJECT SUMMARY According to the Centers for Disease Control and Prevention, insufficient sleep is an epidemic that poses significant clinical and economic impacts. Poor sleep can be caused by impaired sleep homeostasis which regulates sleep need as a function of prior wakefulness. Therefore, determining the cellular basis of sleep homeostasis is necessary to understand underlying causes of abnormal sleep. The biological substrates of sleep homeostasis are incompletely understood, but glial astrocytes may play a central role. Astrocytes are found throughout the brain and modulate compensatory responses to sleep loss. Because astroglial chemical signaling is mediated by changes in intracellular calcium, I hypothesize that astroglial intracellular calcium dynamics contribute to the accumulation and discharge of sleep need. I will test this hypothesis in two Aims: 1) Characterize astroglial calcium dynamics in spontaneous sleep and in response to sleep deprivation; 2) Determine the extent to which astroglial calcium signaling contributes to sleep homeostasis. Intracellular calcium activity in astroglial somata and processes will be measured in vivo with a head-mounted epifluorescent microscope and two-photon microscopy in unanesthetized mice expressing the genetically encoded calcium indicator GCaMP6f selectively in astrocytes. Astroglial calcium dynamics will be simultaneously recorded with sleep-wake behavior, as determined by electroencephalography and electromyography, under physiological conditions, in response to sleep deprivation, and following genetic depletion of astroglial intracellular calcium stores. These studies will be the first to describe astroglial calcium activity in conjunction with electroencephalographic determination of arousal state. The results of these experiments will provide new, mechanistic insights into astroglial mediation of sleep homeostasis.