PDF(Pubmed)
Abstract：
Mammalian hibernators survive prolonged periods of cold and resource scarcity by temporarily modulating normal physiological functions, but the mechanisms underlying these adaptations are poorly understood. The hibernation cycle of thirteen-lined ground squirrels (Ictidomys tridecemlineatus) lasts for 5-7 months and comprises weeks of hypometabolic, hypothermic torpor interspersed with 24-48-h periods of an active-like interbout arousal (IBA) state. We show that ground squirrels, who endure the entire hibernation season without food, have negligible hunger during IBAs. These squirrels exhibit reversible inhibition of the hypothalamic feeding center, such that hypothalamic arcuate nucleus neurons exhibit reduced sensitivity to the orexigenic and anorexigenic effects of ghrelin and leptin, respectively. However, hypothalamic infusion of thyroid hormone during an IBA is sufficient to rescue hibernation anorexia. Our results reveal that thyroid hormone deficiency underlies hibernation anorexia and demonstrate the functional flexibility of the hypothalamic feeding center.
摘要：
哺乳动物冬眠者通过暂时调节正常的生理功能，在长时间的寒冷和资源短缺中存活下来。但是对这些适应的潜在机制知之甚少。十三个衬里的地松鼠（Ictidomystridecemlineatus）的冬眠周期持续5-7个月，包括数周的低代谢，体温过低，散布着24-48小时的类似活跃的间歇唤醒（IBA）状态。我们展示了地松鼠，他们忍受整个冬眠季节没有食物，在IBA期间饥饿可以忽略不计。这些松鼠表现出对下丘脑进食中心的可逆抑制，这样下丘脑弓状核神经元对ghrelin和leptin的促食欲和促食欲作用的敏感性降低，分别。然而,IBA期间下丘脑输注甲状腺激素足以挽救冬眠厌食症。我们的结果表明，甲状腺激素缺乏是冬眠厌食症的基础，并证明了下丘脑喂养中心的功能灵活性。
