Subparaventricular zone pathways to circadian synchrony

室旁区昼夜节律同步途径

基本信息

批准号：
8716117
负责人：
William David Todd
金额：
$ 4.88万
依托单位：
BETH ISRAEL DEACONESS MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-06-27 至 2015-06-26
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8716117
关键词：
Affect Area Automobile Driving Behavior Behavioral Bilateral Body Temperature Cardiovascular Diseases Cells Chronic Circadian Rhythms Contralateral Cre-LoxP Darkness Development Diabetes Mellitus Dorsal Electroencephalography Exons Genes Health Human Hypertension Hypothalamic structure Implant Injection of therapeutic agent Ipsilateral Knockout Mice Laboratory Rat Lesion Lighting Malignant Neoplasms Measures Mediating Mental Depression Motor Activity Mus Neurons Neurotransmitters Obesity Occupations Outcome Output Pathway interactions Pattern Physiological Physiology Population Prevention Publishing Rattus Rattus norvegicus Relative (related person)Reporting Role Schedule Site Sleep Structure System Technology Testing Time Tracer Travel Vesicle Viral Vector Wakefulness circadian pacemaker gamma-Aminobutyric Acid in vivo intraperitoneal neural circuit paraventricular nucleus prevent promoter public health relevance recombinase research study response shift work suprachiasmatic nucleus transmission process vector vesicular GABA transporter

项目摘要

DESCRIPTION (provided by applicant): The subparaventricular zone (SPZ) of the hypothalamus is an important component of the circuitry that synchronizes and drives circadian rhythms of behavior and physiology. The SPZ receives most of the axonal output from the suprachiasmatic nucleus (SCN), the mammalian circadian pacemaker, and further projects to most of the SCN's downstream targets. Physiological and anatomical studies in rats suggest the SPZ is heterogeneous and comprised of subregions differentially modulating particular rhythms. Specifically, dorsal SPZ lesions, defined by the region extending ventrally from the paraventricular nucleus (PVH), selectively disrupt body temperature (Tb) rhythms with minimal impact on locomotor activity (LMA) or sleep/wake rhythms. In contrast, ventral SPZ lesions, defined by the region extending dorsally and caudally from the SCN, profoundly disrupt LMA and sleep/wake rhythms with less effect on Tb. Anterograde tracing from the SPZ in rats further suggests this area is comprised of four anatomically, and perhaps functionally, distinct subregions: the ventromedial and ventrolateral SPZ (vmSPZ, vlSPZ) and the dorsomedial and dorsolateral SPZ (dmSPZ, dlSPZ). Recent developments of certain conditional knockout mice allow for the direct testing of the neurotransmitter-specific role of SPZ subregions in vivo. We seek to gain a better understanding of SPZ organization and outflow and its role in the circadian timing system in mice. Elucidating such pathways may reveal mechanisms by which chronic circadian disruption alters behavior and adversely affects overall health. Aim 1. To assess the role of GABAergic subpopulations of the SPZ in the modulation of circadian rhythms of Tb, LMA, and sleep/wake: The SPZ is primarily comprised of GABAergic neurons, which package GABA into vesicles using VGAT. Using Cre-Lox technology, we will inject a viral vector to delete VGAT expression in SPZ subregions, preventing these cells from releasing GABA. We will record freely moving mice in constant dark, while measuring Tb and LMA using biotelemetry transmitters implanted in the intraperitoneal cavity, and sleep/wake using EEG and EMG recordings. We expect these experiments to identify which populations of GABAergic neurons in the SPZ regulate circadian rhythms of LMA, sleep/wake, and Tb. Aim 2. To delineate efferent projections from GABAergic SPZ neurons and correlate the physiological patterns in Aim 1 with deletion of GABAergic transmission in specific terminal fields: There are no published reports of a detailed analysis of SPZ efferents in mice. The vector used in Aim 1 also traces the efferent projections from transduced neurons and will reveal the projection targets that mediate these rhythms, however, it also traces from non-GABAergic neurons. To clarify the projections likely underlying our effects, we will use mice expressing Cre under the VGAT promoter and a vector expressing the gene for a Cre-dependent tracer to selectively trace SPZ GABAergic projections. We will then compare VGAT deletion in specific targets with physiological responses in Aim 1 to determine SPZ targets regulating specific circadian rhythms.

描述（由申请人提供）：下丘脑的室旁区（SPZ）是同步和驱动行为和生理昼夜节律的电路的重要组成部分。 SPZ 接收来自视交叉上核 (SCN)（哺乳动物昼夜节律起搏器）的大部分轴突输出，并进一步投射到大多数 SCN 下游目标。对大鼠的生理学和解剖学研究表明，SPZ 是异质的，由差异调节特定节律的子区域组成。具体来说，背侧 SPZ 病变（由从室旁核（PVH）向腹侧延伸的区域定义）选择性地扰乱体温（Tb）节律，而对运动活动（LMA）或睡眠/觉醒节律的影响最小。相比之下，腹侧 SPZ 病变（由从 SCN 向背侧和尾侧延伸的区域定义）会严重扰乱 LMA 和睡眠/觉醒节律，但对 Tb 的影响较小。大鼠 SPZ 的顺行追踪进一步表明该区域由四个解剖学上、也许功能上不同的子区域组成：腹内侧和腹外侧 SPZ (vmSPZ, vlSPZ) 以及背内侧和背外侧 SPZ (dmSPZ, dlSPZ)。最近开发的某些条件性基因敲除小鼠可以直接测试体内 SPZ 亚区的神经递质特异性作用。我们寻求更好地了解 SPZ 组织和流出及其在小鼠昼夜节律计时系统中的作用。阐明这些途径可能揭示慢性昼夜节律紊乱改变行为并对整体健康产生不利影响的机制。目标 1. 评估 SPZ 的 GABA 能亚群在调节 Tb、LMA 和睡眠/觉醒昼夜节律中的作用：SPZ 主要由 GABA 能神经元组成，它们使用 VGAT 将 GABA 包装到囊泡中。利用 Cre-Lox 技术，我们将注射病毒载体来删除 SPZ 亚区域中的 VGAT 表达，从而阻止这些细胞释放 GABA。我们将记录在持续黑暗中自由移动的小鼠，同时使用植入腹腔内的生物遥测发射器测量 Tb 和 LMA，并使用 EEG 和 EMG 记录来测量睡眠/唤醒。我们期望这些实验能够确定 SPZ 中哪些 GABA 能神经元群调节 LMA、睡眠/觉醒和 Tb 的昼夜节律。目标 2. 描绘 GABA 能 SPZ 神经元的传出投射，并将目标 1 中的生理模式与特定末端区域中 GABA 能传输的删除相关联：尚无关于小鼠 SPZ 传出神经详细分析的已发表报告。目标 1 中使用的向量还追踪来自转导神经元的传出投射，并将揭示介导这些节律的投射目标，然而，它也追踪来自非 GABA 能神经元的投射。为了阐明我们的影响可能潜在的预测，我们将使用在 VGAT 启动子下表达 Cre 的小鼠和表达 Cre 依赖性示踪剂基因的载体来选择性地追踪 SPZ GABA 能预测。然后，我们将比较特定目标中的 VGAT 缺失与目标 1 中的生理反应，以确定调节特定昼夜节律的 SPZ 目标。