Energy Balance and Control of Physiological Dormancy

能量平衡和体温的恒定是由大脑控制的，与动物身体和环境的变化有关。这里将试图通过研究一种特殊的情况来研究这种调节系统的特征：蜂鸟是已知最小的温血动物之一，在这段短暂的夜间1-10小时内，作为一种节能措施，正常的体温恒定被放弃了。像冬眠的哺乳动物一样，蜂鸟可以进入麻木的生理状态，在这种状态下，代谢率和体温都会大大降低。引发麻木的生理控制系统整合的有关鸟类内部状态和环境的信息将被确定。还将调查麻木在实现长距离迁徙所需的快速和反复体重增加方面的特殊作用。虽然蜂鸟进入了已知鸟类中最深的麻木状态，但几乎每一种被研究的鸟类，以及许多哺乳动物，在能量短缺的时候，都会在一定程度上降低夜间体温和代谢率。麻木似乎也类似于人类的睡眠。因此，蜂鸟的麻木状态为研究一系列普遍重要的生理学基础提供了机会，具有恒定调节规则例外所提供的特殊实验优势。

Energy balance and constancy of body temperature are controlled by the brain in relation to changing conditions of an animal's body and environment. An attempt will be made here to investigate the characteristics of this regulatory system by studying an exceptional situation: the brief nightly period of 1-10 hours when the normal constancy of body temperature is abandoned as an energy conserving measure by one of the smallest known warm- blooded animals, a hummingbird. Like hibernating mammals, hummingbirds can enter a physiological state of torpor, in which metabolic rate and body temperature are greatly reduced. The kind of information about the internal state of the bird and the environment that is integrated by the physiological control system that initiates torpor will be determined. The special role of torpor in making possible the rapid and repeated weight gain necessary to achieve long-distance migration will also be investigated. Although hummingbirds enter the deepest state of torpor known among birds, almost every species of bird studied, as well as many mammals, reduce nighttime body temperature and metabolic rate to some degree in times of energy shortage. Torpor also appears to be analagous to human sleep. Thus torpor in hummingbirds provides an opportunity to study series of generally important physiological fundamentals with the special experimental advantages afforded by an exception to the rule of constant regulation.