Annual Rhythms of Energy Balance and Behavior

描述(由申请人提供)：总体目标是确定身体脂肪储备和下丘脑肽机制，特别是神经肽Y(NPY)在控制日常麻木中所起的作用。每日麻木是一种极端的温度调节形式，进化出来的目的是通过独特的减少能量消耗来帮助动物应对有限的食物供应。将探索整合整体能量平衡和麻木的中枢神经和外周神经机制。西伯利亚仓鼠的年摄食量和体重、繁殖和每日麻木的节律都有很好的记录，而西伯利亚仓鼠是所有实验的模式物种。具体目标包括：1)对比直接内侧视前区(MPOA)注射NPY对体温的影响，特别是其诱导麻痹的能力和影响棕色脂肪组织温度与体温变化的时间；2)了解NPY受体亚型在西伯利亚仓鼠下丘脑中的分布；3)比较和对比MPOA中NPY受体激动剂和拮抗剂对麻痹诱导的影响；4)评价利用神经元特异性神经损伤诱导(NPY&2DG)和自然麻木的MPOA的必要性；5)比较下丘脑室旁核直接注射NPY和NPY受体激动剂对肩周棕色脂肪组织温度(和体温)的影响。

DESCRIPTION (provided by applicant): The overall goal is to characterize the role that body fat reserves and hypothalamic peptide mechanisms, especially neuropeptide Y (NPY), play in controlling daily torpor. Daily torpor is an extreme form of temperature regulation that evolved to help animals contend with limited food availability by uniquely reducing energy expenditure. 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) contrasting the effects of direct intra-medial preoptic area (MPOA) injections of NPY on body temperature, specifically its ability to induce torpor and affect the timing of changes in brown adipose tissue temperature vs. body temperature; 2) developing an anatomical understanding of the distribution of NPY receptor subtypes in the Siberian hamster hypothalamus; 3) comparing and contrasting NPY receptor agonist activation and antagonist inhibition of NPY receptor sites in the MPOA on torpor induction; 4) evaluating the necessity of the MPOA for both induced (NPY & 2DG) and natural torpor using neuron-specific neurotoxic lesions; 5) comparing and contrasting effects of direct injections of NPY and NPY receptor agonists into the paraventricular nucleus of the hypothalamus on interscapular brown adipose tissue temperature (and body temperature).