MOLECULAR FUNCTIONS OF SLEEP: EFFECTS OF AGE/ROLE OF AMP-DEPENDENT PROTEIN KINASE

年龄较大的动物睡眠和觉醒零碎，非快速眼动睡眠较少，增量波幅降低 睡眠中的波浪。这些变化的机制及其后果尚不清楚。在这 提议，我们认为在睡眠和清醒时，细胞能量储存发生了变化 大脑。这种改变会影响AMP依赖的激酶(AMPK)，AMPK的活性对细胞敏感 ATP/AMP比率。当该酶在低细胞能量条件下被激活时，它会促进 能量的释放储存并作用于对抗利用能量的过程，如胆固醇合成 和蛋白质翻译。因此，我们认为这种酶的活性在睡眠和睡眠之间会有所不同。 而AMPK活性改变会导致胆固醇合成和 睡眠和清醒之间的蛋白质翻译。我们认为，细胞的修复分子功能 睡眠包括增加胆固醇合成和蛋白质转化。我们将对这一假设进行调查。 由于年龄较大的动物睡眠更零散，很可能睡眠的这些分子功能将 在这个年龄段受到了损害。这将导致睡眠和睡眠期间大脑胆固醇合成减少 因此，由于胆固醇在细胞膜中起关键作用，因此损害了神经元的功能 信号和突触可塑性。此外，在年龄较大的动物中，细胞能量电荷的变化可能更大 在清醒时迅速，导致更快的蛋白质翻译抑制。由于抑制了 蛋白质翻译将对许多细胞过程产生深远的影响，这很可能是一个变量 这设置了可以持续的清醒时间。为了解决这些假设，我们建议 在老年动物和幼年动物中评估以下情况：a)蛋白质翻译调节的变化 睡眠和清醒；b)睡眠和清醒之间胆固醇合成调节的变化；c) 睡眠和清醒时AMPK磷酸化和活性的变化。此外，为了表明这些 AMPK活性的变化导致睡眠/清醒的变化以及伴随的胆固醇和蛋白质 合成改变，我们将评估局部微量注射阻断酶活性的效果 进入病毒的大脑，表达显性的阴性形式的酶。此项目中的协议 发展一种协调的方法来研究睡眠的分子功能及其在睡眠中的变化 年长的动物。因此，这个项目将使我们对老年人睡眠障碍的认识进入一个新的阶段 提高认识水平，开辟新的干预方法，增强睡眠功能。

Older animals have fragmented sleep and wakefulness, less NREM sleep, and reduced amplitude of delta waves during sleep. The mechanisms for these changes and their consequences are unknown. In this proposal, we argue that during sleep and wakefulness,there is an alteration in the cellular energy stores in brain. This alteration will affect the AMP-dependent kinase (AMPK) whose activity is sensitive to cellular ATP/AMP ratios. When the enzyme is activated under conditions of low cellular energy, it promotes the liberation of energy stores and acts to antagonizeprocesses that utilize energy such as cholesterol synthesis and protein translation. We therefore propose that the activity of this enzyme will vary between sleep and wakefulness, and that alteration in activity of AMPK will lead to alterations in cholesterol synthesis and protein translation between sleep and wakefulness. We propose that restorative molecular functions of sleep include increased cholesterol synthesis and protein translation. This hypothesis will be investigated. Since older animals have more fragmented sleep, it is likely that these molecular functions of sleep will be compromised in this age group. This will lead to decreased cholesterol synthesis in brain during sleep and thereby compromised neuronal function since cholesterol is known to play a key role in membrane signaling and synaptic plasticity. Moreover, in older animals, cellular energy charge may change more rapidly during wakefulness leading to more rapid inhibition of protein translation. Since inhibition of protein translation will have profound effects on many cellular processes, this is likely to be one variable that sets the duration of wakefulness that can be sustained. To address these hypotheses, we propose to assess the following in both old and young animals: a) changes in regulation of protein translation between sleep and wakefulness;b) changes in regulation of cholesterol synthesis between sleep and wakefulness;c) changes in AMPK phosphorylation and activity between sleep and wakefulness. Further, to show that these changes in AMPK activity cause sleep/wake changes along with concomitant cholesterol and protein synthesis changes, we will assess the effects of blocking the activity of the enzyme by local microinjection into brain of a virus expressing a dominant negative form of the enzyme. The protocols in this project develop a coordinated approach to a new study of the molecular functions of sleep and their alterations in older animals. Thus, this project will take our knowledge about sleep disturbances in the elderly to a new level of understanding, opening new approaches for interveningto enhance the functions of sleep.