NEUROBIOLOGICAL STUDIES OF A NOVEL HYPOTHALAMIC PEPTIDE

新型下丘脑肽的神经生物学研究

• 批准号: 6945775
• 负责人: Thomas S Kilduff
• 金额: $ 45.26万
• 依托单位: SRI INTERNATIONAL
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-30 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6945775
• 关键词: bioenergetics; body temperature regulation; calcium flux; chordate locomotion; electroencephalography; electromyography; hypothalamus; immunocytochemistry; in situ hybridization; laboratory rat; locus coeruleus; membrane channels; neurons; neuropeptide receptor; neuropeptides; neuropharmacology; protein localization; receptor expression; sleep; subtraction hybridization; tissue /cell culture; voltage /patch clamp

DESCRIPTION (provided by applicant): Since the initial funding of this grant proposal, the hypocretin/orexin system has been recognized to be a hypothalamic neuropeptide system with widespread excitatory activity. Defects in this system, either presynaptically or postsynaptically, result in the sleep disorder narcolepsy in both animal models and in humans. Based on these and other observations, hypocretin (Hcrt) is now viewed as a central neurotransmitter system in the maintenance of wakefulness. During the next funding period, we propose to examine specific inputs to and outputs from the Hcrt neurons at both the cellular and behavioral levels. We hypothesize that there is an interaction between the Hcrt and the corticotropin releasing factor (CRF) systems. To further understand this relationship, we will (1) determine the origin of CRF-containing afferent innervation of the Hcrt neurons using anterograde tracing from potential CRF afferent sources combined with Hcrt immunohistochemistry and retrograde tracing from the perifornical hypothalamus with CRF-immunohistochemistry; (2) identify the mechanism of action of the excitatory effect of CRF on Hcrt cells; and (3) determine whether an intact Hcrt system is necessary for the anxiogenic effects of CRF. We will identify whether CRF is anxiogenic in hypocretin-ataxin cell knockout mice and evaluate the effect of hypocretin peptides in four anxiety models in wildtype mice. These studies will determine whether the Hcrt system is "downstream" from CRF. We will also determine the response of Hcrt neurons to stimulation by other neurotransmitters that may provide modulatory input to the Hcrt system. We will examine the mechanisms underlying GABAergic inhibition of the Hcrt neurons and determine whether endogenous inhibitory tone exists in this system. We will also examine other potential sources of modulatory input to the Hcrt cells, such as that from the hypothalamic ghrelin and galanin systems. Lastly, we will determine whether subpopulations of Hcrt neurons can be differentiated based on their efferent projections to sleep-related monoaminergic and cholinergic nuclei. To address this question, we will use dual retrograde tracing from different sleep-related regions to determine the extent of co-localization of retrograde markers within Hcrt neurons and the distribution of these markers within the Hcrt neuronal population. The information obtained will elucidate the neural networks related to the Hcrt system and thereby further our understanding of the neurobiological bases of sleep, wakefulness, and the sleep disorder narcolepsy.

描述（由申请人提供）：由于该赠款提案的初步资金，低载素/甲肌蛋白系统已被认为是具有广泛兴奋活动的下丘脑神经肽系统。该系统的缺陷是突触前还是突触后，导致动物模型和人类中的睡眠障碍性疾病。基于这些和其他观察结果，现在将低载素（HCRT）视为维持觉醒的中心神经递质系统。在下一个资金期间，我们建议在细胞和行为水平上检查HCRT神经元的特定输入和输出。我们假设HCRT和皮质激素释放因子（CRF）系统之间存在相互作用。为了进一步理解这种关系，我们将使用潜在的CRF传入源与HCRT免疫组织化学结合使用的CRF传入来源的顺行迹象来确定HCRT神经元含有CRF的传入神经元神经的起源，并从HCRT免疫组织化学和逆行下丘脑与CRF-Mumuno-Mumuno-Muno-Muno-Mumuno Hastericchecontrive中逆行逆行追踪； （2）确定CRF对HCRT细胞的兴奋作用的作用机理； （3）确定完整的HCRT系统是否对于CRF的焦虑作用是必需的。我们将确定CRF在低载素 - 阿塔X型细胞基因敲除小鼠中是否具有抗焦虑作用，并评估野生型小鼠四种焦虑模型中低载素肽的作用。这些研究将确定HCRT系统是否来自CRF的“下游”。我们还将确定HCRT神经元对其他神经递质刺激的反应，这些神经递质可能为HCRT系统提供调节性输入。我们将检查HCRT神经元的GABA能抑制的基础机制，并确定该系统中是否存在内源性抑制性张力。我们还将检查针对HCRT细胞的其他潜在调节输入来源，例如下丘脑生长素蛋白和甘丙蛋白系统。最后，我们将确定HCRT神经元的亚群是否可以根据其对睡眠相关的单胺能和胆碱能核的传染性投影来分化。为了解决这个问题，我们将使用来自不同睡眠相关区域的双重逆行跟踪来确定HCRT神经元内逆行标记的共定位程度以及HCRT神经元种群中这些标记物的分布。获得的信息将阐明与HCRT系统相关的神经网络，从而进一步了解睡眠，清醒和睡眠障碍性疾病的神经生物学基础。