Pontine Control of REM Atonia

描述(申请人提供)：快速眼动睡眠的一个重要特征是几乎所有肌肉瘫痪。在REM睡眠行为障碍(RBD)中，缺乏REM张力可以出现做梦。这种疾病与帕金森氏症等神经退行性疾病密切相关，通常在疾病涉及包括脑桥在内的下部脑干的早期阶段出现。大量证据表明，脑桥背外侧下核(SLD)的神经元，也被称为核下核，在REM睡眠期间产生肌肉张力。该区域的损伤会产生没有紧张症的REM，而药物激活则会触发REM样状态。我们最近发现SLD中的谷氨酸能REM能神经元直接投射到脊髓中的甘氨酸能/GABA能前运动神经元。我们的假设是，这些脊髓投射SLD(SLDSP)神经元在REM睡眠中肌肉张力的产生中起着关键作用。我们将用膜片钳记录的方法研究胆碱能、单胺能和食欲素能传入SLDSP神经元的电生理作用。我们将在脊髓内微量注射荧光示踪剂，逆行预标记SLDSP神经元，然后使用这些动物进行切片记录。在目标1和目标2中，我们将确定对胆碱能和单胺能输入的电生理反应。我们将确定它们在突触前和突触后的作用，并确定它们的受体亚型及其电生理介导的机制。在目标3中，我们将重点介绍食欲素能输入。我们发现SLDSP神经元并不直接受到食欲素的影响，相反，食欲素增加了对这些神经元的GABA能突触输入。我们将通过使用可诱导的增食欲素受体Ox1R和Ox2R敲入小鼠的抢救实验来确定这种GABA能输入的来源。这些小鼠出生时就缺乏Ox1R或Ox2R，或者两者都缺乏。我们将把含有Cre重组酶的腺相关病毒载体注射到这些小鼠的特定脑区，以诱导食欲素受体的局部挽救，并恢复GABA能突触进入SLDSP神经元的食欲素能调节。总体而言，这些实验将有助于确定调节REM张力神经元的生理学基础。此外，这些研究将为了解增食欲素对REM-张力神经元的作用机制，以及它们的缺失如何导致猝倒，以及RBD中REM-张力神经元的控制提供重要的见解。与公众健康相关在正常的快速眼动(REM)睡眠中，肌肉张力的丧失会阻止人们实现他们的梦想。REM睡眠行为障碍(RBD)和猝倒可能是由控制REM-张力的回路功能障碍引发的。我们实验的目的是定义REM睡眠障碍的生理学，更好地了解RBD和猝倒的神经生物学，并为开发更有效的治疗方法提供必要的见解。

DESCRIPTION (provided by applicant): A defining feature of REM sleep is paralysis of nearly all muscles. In REM sleep behavior disorder (RBD), the absence of REM atonia permits the appearance of dream enactment. This disorder is strongly associated with neurodegenerative diseases such as Parkinson's disease, and it often appears in early stages when the disease involves the lower brainstem including the pons. Considerable evidence demonstrates that neurons of the sublaterodorsal (SLD) nucleus of the pons, also known as the subcoreuleus, generate muscle atonia during REM sleep. Lesions of this area produce REM without atonia while pharmacological activation triggers a REM-like state. We recently found that glutamatergic REM-active neurons in the SLD directly project to the glycinergic/GABAergic premotorneurons in the spinal cord. Our hypothesis is that these spinal projecting SLD (SLDsp) neurons play a critical role in the generation of muscle atonia during REM sleep. We will examine the electrophysiological actions of the cholinergic, monoaminergic and orexinergic afferents to the SLDsp neurons using patch- clamp recordings in a slice preparation. We will retrogradely prelabel the SLDsp neurons with fluorescent tracers microinjected in the spinal cord, and then use these animals for slice recordings. In Aim 1, and Aim 2, we will determine the electrophysiological responses to cholinergic and monoaminergic inputs. We will determine their pre- and postsynaptic effects, and we will identify their receptor subtypes and their electrophysiologically-mediated mechanisms. In Aim 3, we will focus on orexinergic inputs. We have found that SLDsp neurons are not directly affected by orexin, but instead orexin increases GABAergic synaptic input to these neurons. We will identify the source of this GABAergic input with a rescue experiment using inducible orexin receptor Ox1R and Ox2R knock-in mice. These mice are born lacking Ox1R or Ox2R or both. We will place injections of an adeno-associated viral vector containing Cre recombinase into specific brain regions of these mice to induce focal rescue of orexin receptors and to restore the orexinergic modulation of GABAergic synaptic input to the SLDsp neurons. Overall these experiments will help define the physiology underlying the regulation of REM-atonia neurons. In addition, these studies will provide essential insights into the mechanism for orexin effects on REM-atonia neurons, and how their absence results in cataplexy, as well as into the control of the REM-atonia neurons in RBD. PUBLIC HEALTH RELEVANCE During normal Rapid Eye Movement (REM) sleep, there is loss of muscle tone that prevents people from acting out their dreams. REM sleep behavior disorder (RBD) and cataplexy may be triggered by the dysfunction of the circuitry that controls REM-atonia The goal of our experiments is to define the physiology of REM sleep atonia, to better understand the neurobiology of RBD and cataplexy and to provide essential insights for the development of more effective treatments.