Role of lateral hypothalamus projections in opioid withdrawal-induced sleep deficits

项目摘要。处方阿片类药物，如羟考酮是非常有效的镇痛药，因此几乎 阿片类药物滥用和阿片类药物使用障碍（OUD）的发生率很高， 自1999年以来，美国估计有40万人死亡。OUD的治疗过程主要受到 阿片类药物戒断综合征：人类最普遍的阿片类药物戒断症状之一， 睡眠-主要是快速眼动睡眠减少和失眠。尽管OUD的失眠会使人衰弱， 关于阿片类药物戒断对睡眠动力学的影响以及睡眠相关神经元的相关作用知之甚少。 大脑回路然而，在与开放式城市发展有关的区域和已知的 唤醒网络参与睡眠。特别是，阿片类药物戒断刺激外侧下丘脑（LH）释放 神经肽食欲素（ORX）进入丘脑室旁核（PVT）。激活PVT， 反过来，已被证明可以促进觉醒和负面影响，这是阿片类药物戒断的两个标志。通过 探测PVT内LH ORX介导的传输，因此我们可以确定这些网络是否 阿片类药物戒断对睡眠的影响。此外，目前的睡眠方法 脑电图（EEG）分析极大地限制了睡眠动力学的描述程度- 通过对主观识别的睡眠阶段求平均来离散化睡眠期间的大脑状态。通过使用 客观、高分辨率的脑电统计信号处理和建模方法，我们可以更好地了解 阿片类药物使用和戒断对睡眠期间神经振荡动力学的影响。基于文献和 我们自己的初步数据显示，羟考酮戒断诱导的PVT激活和 睡眠结构和动力学，我们假设阿片类药物戒断通过改变 LH-PVT ORX神经元的功能。具体目标1将描述羟考酮戒断对睡眠的影响 结构和睡眠动力学。我们将描述10-d的时变效应 从慢性、递增剂量羟考酮戒断对睡眠结构和振荡动力学的影响 连续记录EEG、EMG和体温。具体目标2将确定ORX LH神经元是否 羟考酮戒断引起的睡眠变化所必需的。我们将使用交叉病毒载体 使用DREADD选择性激活或抑制LH抑制PVT神经元的方法，量化对睡眠的影响 架构和动力学。为了测试ORX的特定作用，将给予ORX拮抗剂苏沃雷生。 有或没有DREADD介导的LH/PVT调节。如果激活LH、PVT或ORX投射介导 阿片类药物诱导的睡眠中断，那么这些投射的抑制将减少，而激活将增加， 羟考酮戒断导致的睡眠不足与脑电图振荡机制的知识配对，这些 实验将提供LH和PVT作用的增强理解，提示更具体的 未来干预研究的机制目标。

Project Summary. Prescription opioids such as oxycodone are highly effective analgesics and hence almost ubiquitously prescribed, resulting in high rates of abuse and opioid use disorder (OUD), which has resulted in an estimated 400,000 deaths in the US since 1999. The treatment course of OUD is primarily challenged by the opioid withdrawal syndrome: one of the most ubiquitous opioid withdrawal symptoms in humans is disrupted sleep—primarily a reduction in REM sleep and insomnia. Despite the debilitating effects of insomnia in OUD, there is little known on the impact of opioid withdrawal on sleep dynamics and the relevant role of sleep-related brain circuits. However, promising linkages have been shown between regions related to OUD and known arousal networks involved in sleep. In particular, opioid withdrawal stimulates lateral hypothalamic (LH) release of the neuropeptide orexin (ORX) into the paraventricular nucleus of the thalamus (PVT). Activation of the PVT, in turn, has been shown to promote wakefulness and negative affect, two hallmarks of opioid withdrawal. By probing LH ORX-mediated transmission within the PVT, we can therefore determine if these networks are necessary for the effect of opioid withdrawal on sleep. Additionally, current approaches to sleep electroencephalogram (EEG) analysis greatly limit the degree to which sleep dynamics can be described— discretizing the brain state during sleep by averaging over subjectively-identified sleep stages. By using objective, high-resolution EEG statistical signal processing and modeling approaches, we can better understand the effect of opioid use and withdrawal on neural oscillatory dynamics during sleep. Based on the literature and our own preliminary data showing oxycodone withdrawal-induced activation of the PVT and robust changes in sleep architecture and dynamics, we hypothesize that opioid withdrawal disrupts sleep via changes in the function of LHPVT ORX neurons. Specific Aim 1 will characterize the effect of oxycodone withdrawal on sleep architecture and sleep dynamics in male and female rats. We will characterize the time-varying effects of 10-d of withdrawal from chronic, escalating-dose oxycodone on sleep architecture and oscillatory dynamics using continuous recording of EEG, EMG, and temperature. Specific Aim 2 will determine if ORX LH neurons are necessary for oxycodone withdrawal-induced changes in sleep. We will use an intersectional viral vector approach with DREADDs to selectively activate or inhibit LHPVT neurons, quantifying the effect of on sleep architecture and dynamics. To test for a specific role of ORX, the ORX antagonist suvorexant will be administered with or without DREADD-mediated LHPVT modulation. If activation of LHPVT ORX projections mediates opioid-induced sleep disruptions, then inhibition of these projections will reduce, whereas activation will increase, oxycodone withdrawal-induced sleep deficits. Paired with a knowledge of EEG oscillatory mechanisms, these experiments will provide an enhanced understanding of the role LH and PVT, suggesting more specific mechanistic targets for future interventional studies.