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

项目摘要。处方类阿片类药物，如羟考酮，是高效的止痛药，因此几乎 无处不在的处方，导致高滥用和阿片使用障碍(OUD)，这导致 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 阿片戒断综合征：人类最普遍的阿片戒断症状之一是中断 睡眠--主要是快速眼动睡眠和失眠的减少。尽管失眠会使人虚弱，但在乌德， 阿片类药物戒断对睡眠动力学的影响以及与睡眠相关的相关作用鲜为人知 大脑回路。然而，与OUD相关的区域和已知区域之间已显示出有希望的联系 与睡眠有关的唤醒网络。特别是，阿片类药物的戒断刺激了下丘脑外侧区(LH)的释放 神经肽增食欲素(ORX)注入丘脑室旁核(PVT)。激活PVT， 反过来，已被证明促进觉醒和负面情绪，这是阿片类药物戒断的两个特征。通过 探测LHORX介导的PVT内的传播，因此我们可以确定这些网络是否 对于阿片类药物戒断对睡眠的影响是必要的。此外，目前的睡眠方法 脑电(EEG)分析极大地限制了对睡眠动力学的描述程度-- 通过对主观确定的睡眠阶段进行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，我们可以更好地理解 阿片类药物的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的戒断通过改变睡眠 LH、、PVT、ORX神经元的功能。具体目标1将描述羟考酮停药对睡眠的影响 雄性和雌性大鼠的结构和睡眠动力学。我们将描述10-d的时变效应。 停用慢性递增剂量羟考酮对睡眠结构和振荡动力学的影响 连续记录脑电、肌电和体温。特定目标2将确定ORX LH型神经元是否 对羟考酮戒断引起的睡眠改变是必要的。我们将使用一种交叉型病毒载体 应用DREADDS选择性激活或抑制LHPVT神经元，量化对睡眠的影响 建筑和动力学。为了测试ORX的特定作用，将使用ORX拮抗剂Suvorexant 使用或不使用DREADD介导的LHPVT调节。如果激活LH、、PVT或X投射 阿片类药物诱导的睡眠中断，那么对这些投射的抑制将减少，而激活将增加， 羟考酮戒断引起的睡眠障碍。再加上对脑电振荡机制的了解，这些 实验将加深对黄体生成素和PVT的作用的理解，建议更具体 未来干预性研究的机制靶点。

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.