Spontaneous daily torpor and fasting-induced torpor in Djungarian hamsters are characterized by distinct patterns of metabolic rate
Spontaneous daily torpor and fasting-induced torpor in Djungarian hamsters are characterized by distinct patterns of metabolic rate
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DOI：
10.1007/s00360-014-0882-4
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发表时间：
2015-04-01
影响因子：
2
通讯作者：
Steinlechner, Stephan
中科院分区：
文献类型：
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作者：
Diedrich, Victoria;Kumstel, Simone;Steinlechner, Stephan
Djungarian仓鼠是一种啮齿类动物，在适应冬季条件时会表现出自发性每日麻痹（SDT），在夏季也会表现出禁食诱导的麻痹（FIT）。在早期的报告中，我们认为这两种体温调节现象在几个参数上有所不同。在本研究中，我们通过显示SDT和FIT之间的代谢率模式不同来进一步完成这种比较。与FIT回合相比，SDT回合明显更长更深。此外，呼吸商措施支持的观点，SDT是从一个国家的能量平衡，而FIT似乎是一个紧急关闭的能源需求产热由于能源短缺进入。在第二个实验中，我们还证实，在仓鼠的麻木季节短暂的食物限制增加SDT的频率，但不影响其深度或持续时间。虽然冬季驯化的动物可以灵活地改变麻痹的频率，以保持能量平衡，我们也发现了麻痹的表达模式，类似于FIT，而不是SDT的证据。因此，如果能量挑战不能再用增加的SDT表达来补偿，仓鼠似乎在负能量平衡中被驱使，导致FIT作为最后的手段。
The Djungarian hamster is a rodent species that expresses both spontaneous daily torpor (SDT) when acclimated to winter conditions as well as fasting-induced torpor (FIT) during summer. In an earlier report we argued that these two thermoregulatory phenomena differ in several parameters. In the present study, we further complete this comparison by showing that metabolic rate patterns differ between both SDT and FIT. SDT bouts were significantly longer and deeper compared to FIT bouts. Additionally, respiratory quotient measures support the view that SDT is entered from a state of energetic balance while FIT appears to be an emergency shutdown of energy demanding thermogenesis due to a shortage of energy sources. In a second experiment, we also confirm that brief periods of food restriction during the hamsters' torpor season increase the frequency of SDT, but do not affect its depth or duration. Although winter-acclimated animals could flexibly alter torpor frequency in order to stay in energetic balance, we also found evidence for torpor expression patterns that resembled FIT, rather than SDT. Consequently, if energetic challenges cannot be compensated with increased SDT expression any longer, the hamsters seem to be driven in a negative energy balance resulting in FIT as a last resort.