ACT 3: SLEEP DEPRIVATION STRESS & ENERGY METABOLISM

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。这个实验室的长期目标是更好地了解哺乳动物对压力做出反应的生理和生化机制。研究人员利用Spraogue-Dawley大鼠，建议采用一种有效的应激范式，即睡眠剥夺，以研究在许多天的时间过程中，睡眠剥夺是如何导致应激诱导的病理生理学发展的。持续的睡眠缺失会导致两个有趣的特征，这两个特征是使用其他标准的应激模式所不能观察到的，比如固定或电击脚底。睡眠不足的动物逐渐增加其能量消耗，因此在压力开始的几天内，其新陈代谢显著增加。代谢率的升高与明显的吞噬功能亢进相一致。睡眠不足与能量负平衡有关，体重的稳步下降就是明证。此外，负能量平衡伴随着动物进入蛋白质和卡路里营养不良的状态，这不能用消化效率的下降或糖尿病等消耗性疾病的新生来解释。鉴于这种应激模式及其相关病理的效力，值得注意的是，人们对发生的潜在生理和生化变化知之甚少。研究人员的意图是剖析这些属性的元素，以进一步了解睡眠剥夺相关的病理生理学。因此，提出了如下的工作假设：睡眠剥夺导致新陈代谢的重组，特定的细胞过程对标准代谢率的贡献显著增加。为了验证这一假设，我们制定了三个具体目标。目的1是通过测量O2消耗和CO2产生来确定应激诱导的整个动物标准代谢率(SMR)变化的时间进程。目的2将通过输注放射性核素标记的微球来测量组织血流量的变化，以确定哪些组织和器官是应激引起的SMR升高的原因。目的3试图通过确定增加能量消耗的途径来阐明导致负能量平衡的生化机制，同时重点关注线粒体质子泄漏。这一应用的相关性在于，睡眠剥夺并不适合通常的应激模式，因为它具有相当常见的特征，如能量负平衡、吞噬过度和特殊的内分泌特征。最重要的是，人们几乎对能量代谢的途径和机制一无所知，因为睡眠被剥夺时，能量代谢会变得强烈升高。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The long-term goal of this laboratory is to better understand the physiological and biochemical mechanisms by which mammals respond to stress. Using Sprague-Dawley rats, the investigators propose to employ a potent stress paradigm, sleep deprivation to investigate how its enforcement over a time course of many days results in the development of stress- induced pathophysiology. Sustained loss of sleep results in two interesting features that are not observed using other standard stress paradigms such as immobilization or electric foot shock. The sleep deprived animal progressively increases its energy expenditure so that within days of onset of the stress, its metabolism increases significantly. This elevation in metabolic rate is coincident with pronounced hyperphagia. Sleep denial is associated with a negative energy balance, as evidenced by steady loss in body weight. In addition, the negative energy balance is accompanied by the animal entering a state of protein and caloric malnutrition that cannot be explained by declines in digestive efficiency, or nascence of wasting diseases such as diabetes. Given the potency of this stress paradigm and its associated pathologies, it is remarkable is that more is not known about the underlying physiological and biochemical changes that occur. It is the intent of the investigators to dissect elements of these attributes to further understanding of sleep deprivation associated pathophysiology. Therefore, the following working hypothesis is proposed: that sleep deprivation causes a reorganization of metabolism, and that specific cellular processes contributing to standard metabolic rate become markedly increased. To test this hypothesis, three Specific Aims have been developed. Aim 1 is to determine the time course of stress-induced changes in whole animal standard metabolic rate (SMR) by measuring O2 consumption and CO2 production. Aim 2 will establish which tissues and organs are responsible for stress induced elevation of SMR by measuring changes in tissue blood flow via infusion of radionuclide labeled microspheres. Aim 3 seeks to elucidate the biochemical mechanisms responsible for the developing negative energy balance by determining avenues for increased energy dissipation, while focusing on mitochondrial proton leakage. The relevance of this application is that sleep deprivation does not fit the usual stress paradigm because of its rather usual characteristics such as development of negative energy balance, hyperphagia, and peculiar endocrine profiles. Most importantly, practically nothing is known about the pathways and mechanisms of energy metabolism that become strongly elevated as sleep is denied.