Hibernation in Tenrecs

目前关于哺乳动物冬眠的观点是基于传统的模型，如地松鼠。在这些模型中，冬眠动物会周期性地在新陈代谢低迷的间歇恢复到活跃水平。在这项研究中，将使用一种独特的冬眠模型。普通的藤虫（Tenrec ecaudatus）起源于马达加斯加，与所有其他已知的冬眠动物不同，它们不会周期性地从冬眠中醒来。此外，这些哺乳动物的活动体温变化很大，这使得在相同体温下，活动和冬眠的触角可以直接进行比较。这项研究将确定与冬眠相关的代谢储蓄的程度和持续时间。此外，研究将确定猫的体温和冬眠状态如何影响肾功能、蛋白质合成和蛋白质降解。预计这项研究不仅将揭示这种新型冬眠形式的潜在机制，而且将为冬眠的进化提供见解。学生们将在这个项目的整个过程中接受研究训练，拓展工作将包括制作一个关于冬眠的电视节目。Tenrecs可能是现存最接近早期胎盘哺乳动物祖先的代表。令人惊讶的是，人们对藤蔓的生理知之甚少，对它们不寻常的冬眠方式就更不了解了。常见的腾趾动物，tenrec ecaudatus，通常会经历很大的体温波动，我们发现这些动物经历了一种新的冬眠形式，动物在整个南方的冬天都一直昏昏欲睡。即使是在温暖的环境中，它们也不会像其他小型冬眠动物（如地松鼠）那样醒来。研究人员将结合呼吸测量与心率、血压和组织氧合的遥测测量，以了解代谢抑制的能量学。由于重要的体内平衡过程，如肾功能和蛋白质代谢，基本上局限于像地松鼠这样的啮齿动物的回合间唤醒，因此，在田鼠中缺乏回合间唤醒，就回避了这些过程的状态问题。它们将决定肾小球滤过和肾血流量如何受到体温和冬眠的影响。此外，还将监测油菜在冬眠期间的转录、翻译和蛋白质降解状况。这些数据将作为理解蝙蝠冬眠的重要机制基础，更重要的是，将作为理解回合间唤醒的功能和进化的平台——这是所有其他已知的小型哺乳动物冬眠的共同特征。

The current views about mammalian hibernation were developed using traditional models such as the ground squirrel. In these models, hibernators periodically rewarm to active levels between bouts of depressed metabolism. In this research, a unique model of hibernation will be used. Common tenrecs (Tenrec ecaudatus) originate from Madagascar and in contrast to all other known hibernators, do not periodically arouse from hibernation. Moreover, these mammals have a very variable active body temperature, which allows for direct comparison between active and hibernating tenrecs at the same body temperatures. This research will determine the extent and duration of metabolic savings associated with hibernation. In addition, studies will determine how kidney function, protein synthesis, and protein degradation are affected by body temperature and hibernation status in tenrecs. It is anticipated that this research will not only reveal the underlying mechanisms for this novel form of hibernation, but provide insight into the evolution of hibernation. Students will receive research training throughout the course of this project and outreach efforts will include development of a television program on hibernation. Tenrecs may be the closest extant representative to the early placental mammal ancestor. Surprisingly little is known of the physiology of tenrecs and even less is known about their unusual mode of hibernation. The common tenrec, Tenrec ecaudatus, normally experiences wide fluctuations in body temperature and we found these animals experience a novel form of hibernation wherein animals are consistently lethargic throughout the Austral winter. Even when handled or held at warm temperatures, tenrecs do not arouse to the extent seen in other small hibernators such as ground squirrels. The investigators will combine respirometry measurements with telemetric measurements of heart rate, blood pressure, and tissue oxygenation, to understand the energetics of metabolic suppression. Since vital homeostatic processes such as renal function and protein metabolism are essentially restricted to the interbout arousal in rodents like ground squirrels, the lack of an interbout arousal in the tenrecs begs the question of the status of these processes. They will determine how tenrec glomerular filtration and renal blood flow are affected by body temperature and hibernation. In addition, the status of transcription, translation, and protein degradation during hibernation in tenrecs will be monitored. These data will serve as an important mechanistic foundation for understanding hibernation in tenrecs and, importantly, will serve as a platform for understanding the function and perhaps evolution of the interbout arousal- a feature common to all other known small mammal hibernators.