Mechanisms Governing the Estrogenic Modulation of Sleep

高质量的睡眠对保持身体健康至关重要。人们越来越认识到性 睡眠和节律紊乱的差异。睡眠不足、失眠等抱怨多了~40% 女性比男性更普遍。然而，从历史上看，女性和雌性动物在研究中的代表性不足， 睡眠及其障碍虽然性腺类固醇和性别是睡眠中断的危险因素 和失眠，卵巢类固醇和睡眠之间的关系知之甚少。广泛、长期 本申请的目的是了解雌激素的细胞机制和功能后果， 介导的警戒状态变化。从以前的研究结果已经确定，雌二醇（E2）的作用， 中位视前核（MnPO）中的神经元是必要的，足以使总睡眠减少约50%的基线。 女性然而，我们的数据提出了一个有趣的悖论：E2抑制睡眠，同时显着增加 细胞外腺苷，一种有效的睡眠诱导剂在MnPO。最近的调查结果和初步数据已经开始 来解释这个明显的矛盾结果表明：（1）E_2能阻断MnPO诱导的睡眠， 腺苷A2 A受体活化和腺苷A1受体活化的作用或化学发生 MnPO星形胶质细胞的活化模拟E2对睡眠的抑制。总之，这些发现使我们找到了 假设E2诱导的高水平的细胞外腺苷启动了腺苷能平衡的转变， 激活MnPO睡眠神经元的A2 A兴奋性音调变为抑制睡眠神经元的A1 R抑制性音调 MnPO星形胶质细胞的E2刺激负责腺苷的增加。 我们提出了四个独立但相关的目标，以解决我们知识中的以下差距， 对于了解雌激素调节睡眠的潜在机制至关重要：（1）MnPO的增加是否 E2诱导的睡眠抑制所需的细胞外腺苷？(2)是MnPO腺苷A1的激活 受体所需的E2诱导的睡眠抑制？(3)是MnPO腺苷A2 A受体的抑制 E2引起的睡眠抑制所需的能量和（4）E2刺激MnPO星形胶质细胞是否需要增加 腺苷和睡眠抑制的作用吗我们通过结合现代的 神经科学技术，包括GAD 1-Cre转基因大鼠系，快速扫描循环伏安法（FSCV）， 腺苷、纤维光度学和化学遗传学来研究雌激素对睡眠的调节。 在比较和对比两性之间的细胞机制方面具有启发性价值， 这种方法经常揭示新的和以前未知的神经可塑性机制。因此，我们有 包括比较性别作为一个生物因素，除了雌激素对睡眠机制的影响。 推进我们对E2调节睡眠机制的理解的重要性在于， 有可能揭示睡眠障碍根源的新观点。这样的理解将提供 有价值的见解，导致更好的治疗方法，使两性受益。

Quality sleep is imperative for the maintenance of good health. There is a growing recognition of sex disparities in sleep and rhythm disorders. Complaints such as insufficient sleep and insomnia are ~40% more prevalent in women than men. Yet, historically, women and female animals are underrepresented in studies of sleep and its disorders. While gonadal steroids and gender are implicated as risk factors for sleep disruptions and insomnia, the relationship between ovarian steroids and sleep is poorly understood. The broad, long-term objective of the application is to understand the cellular mechanisms and functional consequences of estrogen- mediated changes in vigilance states. Findings from the previous grant have established that estradiol (E2) acting in the median preoptic nucleus (MnPO) is necessary and sufficient to reduce total sleep by ~50% of baseline in females. However, our data present an intriguing paradox: E2 suppresses sleep while markedly increasing extracellular adenosine, a potent inducer of sleep in the MnPO. Recent findings and preliminary data have begun to shed light on this apparent contradiction. Our findings in the MnPO show that (1) E2 blocks the sleep inducing actions of adenosine A2A receptor activation and activation of the adenosine A1 receptors or chemogenetic activation of MnPO astrocytes mimic E2 suppression of sleep. Together, these findings have led us to our central hypothesis that the E2-induced high levels of extracellular adenosine initiate a shift in adenosinergic balance from an A2A excitatory tone that activates MnPO sleep neurons to an A1R inhibitory tone that inhibits the sleep-neurons and E2 stimulation of MnPO astrocytes is responsible the increase in adenosine. We propose four independent, but related aims to address the following gaps in our knowledge that are critical to understanding the mechanisms underlying estrogenic regulation of sleep: (1) Is the increase in MnPO extracellular adenosine required for E2-induced suppression of sleep? (2) Is the activation of MnPO adenosine A1 receptors required for E2-induced suppression of sleep? (3) Is the suppression of MnPO adenosine A2A receptors required for E2-induced suppression of sleep? and (4) Is E2 stimulation of MnPO astrocytes required for increases in adenosine and sleep suppression? We approach these questions through a combination of modern neuroscience techniques that include a GAD1-Cre transgenic rat line, fast scan cyclic voltammetry (FSCV) of adenosine, fiber photometry and chemogenetics to investigate estrogenic regulation of sleep. There is heuristic value in comparing and contrasting cellular mechanisms between the sexes as this approach has frequently reveal novel and previously unknown mechanisms of neural plasticity. Thus, we have included a comparison of sex as a biological factor in addition to estrogenic influences on sleep mechanisms. The significance of advancing our understanding of the mechanisms underlying E2 modulation of sleep is the potential to uncover new perspectives on the root causes of sleep disturbances. Such understanding will provide valuable insights that lead to better therapeutics benefiting both sexes.