Annual Rhythms of Energy Balance and Behavior

描述（由申请人提供）：总体目标是描述下丘脑神经肽Y机制在控制日常麻木中的作用，这是一种极端的温度调节形式，旨在帮助动物应对有限的食物供应。将探讨综合能量平衡和麻木的中枢和外周神经机制。西伯利亚仓鼠（Phodopus sungorus）是所有实验的模式物种，其食物摄取量、体重、繁殖和日常睡眠的年度节律都有很好的记录。具体目的包括：1)测量和对比冬眠和非冬眠西伯利亚仓鼠下丘脑神经肽和神经肽mRNA水平，特别是神经肽Y水平；2)检查神经肽Y受体拮抗剂预处理是否可以预防自发性和/或2dg诱导的麻木；3)确定连续输注NPY是否会产生延长的低温；4)评估通过阻断褐色脂肪组织的去甲肾上腺素受体来抑制产热是否会产生类似冬眠的低温。

DESCRIPTION (provided by applicant): The overall goal is to characterize the role that hypothalamic neuropeptide Y mechanisms play in controlling daily torpor, an extreme form of temperature regulation that evolved to help animals contend with limited food availability. The central and peripheral neural mechanisms integrating overall energy balance and torpor will be explored. Annual rhythms of food intake and body mass, reproduction, and daily torpor are well documented in the Siberian hamster (Phodopus sungorus), the model species in all experiments. Specific aims include: 1) measuring and contrasting hypothalamic neuropeptide and neuropeptide mRNA levels, especially neuropeptide Y, in torpid and non-torpid Siberian hamsters; 2) examining whether pretreatment with a neuropeptide Y receptor antagonist can prevent spontaneous and/or 2DG-induced torpor; 3) determining whether successive NPY infusions produce prolonged hypothermia; 4) evaluating whether inhibiting thermogenesis by blocking norepinephrine receptors at brown adipose tissue produces torpor-like hypothermia. Much remains that we do not understand about the physiological mechanisms underlying the control of energy balance and thermoregulation. Delineating the interaction between specific neural pathways and neurotransmitters 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, especially organ transplants. Little is known at this time of the mechanism that allows Siberian hamsters and several other 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.