ANNUAL RHYTHMS OF ENERGY BALANCE AND BEHAVIOR

该提案的总体目标是进一步表征日常麻木的启动和表达背后的神经内分泌机制，这是一种极端形式的温度调节，其进化是为了帮助动物应对有限的食物供应。 我们将探讨麻木与整体能量平衡和身体脂肪储存的关系。 西伯利亚仓鼠（Phodopus sungorus）是所有实验中的模型物种，其每日麻木的年度节律得到了充分记录。 具体目标包括：1）阐明体内脂肪储存减少与其在启动冬眠过程中的反馈机制之间的关系； 2) 表征瘦素作为抑制麻木起始的代谢信号的作用； 3）探索NPY在迟钝中的作用； 4) 确定间脑机制在日常麻木状态启动中的作用 对于能量平衡和体温调节控制的生理机制，我们仍有很多不了解的地方。 在像西伯利亚仓鼠这样的模型系统中描绘代谢反馈信号和日常麻木之间的相互作用可以为一般哺乳动物，特别是人类这些过程的调节提供重要的见解。 更好地了解可逆性低温的机制具有医学意义。 与低温同时发生的新陈代谢、血流量等的减少在许多类型的大手术中可能非常有益。 目前，我们对西伯利亚仓鼠和其他几种哺乳动物物种遭受对人类和大多数其他哺乳动物致命的体温过低的机制知之甚少。拟议的研究解决了调节生物学的基本问题，从而提供了建立适用于所有哺乳动物的一般原则的机会。

The overall goal of this proposal is to further characterize the neuroendocrine mechanisms that underlie the initiation and expression of daily torpor, an extreme form of temperature regulation that evolved to help animals contend with limited food availability. The relation of torpor to overall energy balance and body fat stores will be explored. Annual rhythms of daily torpor are well documented in the Siberian hamster (Phodopus sungorus), the model species in all experiments. Specific aims include: 1) clarifying the relation between decreases in body fat stores and its feedback mechanisms in the initiation of torpor; 2) characterizing the role of leptin as a metabolic signal inhibiting initiation of torpor; 3) exploring the role of NPY in torpor; 4) determining the role of diencephalic mechanisms in initiation of daily torpor There is much that we still do not understand about the physiological mechanisms underlying the control of energy balance and thermoregulation. Delineating the interaction between metabolic feedback signals and daily torpor in a model system like the Siberian hamster could provide important insights into the regulation of these processes for mammals in general and humans in particular. A better understanding of the mechanisms of reversible hypothermia is of medical import. The reduced metabolism, blood flow, etc. coincident with hypothermia may be very beneficial during many types of major surgery. At this time, we know little of the mechanism that allows Siberian hamsters and several other mammalian species to undergo hypothermia which is lethal to humans and most other mammals. The proposed research addresses fundamental questions in regulatory biology and, thereby, affords the opportunity of establishing general principles applicable to all mammals.