Nagashima Sakimi, Yamaguchi Sho T, Zhou Zhiwen, Norimoto Hiroaki
Graduate School of Science, Nagoya University, Nagoya, Japan.
Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
J Biol Rhythms. 2024 Dec;39(6):607-613. doi: 10.1177/07487304241273190. Epub 2024 Sep 10.
Animals frequently experience temperature fluctuations in their natural life cycle, including periods of low temperatures below their activity range. For example, poikilothermic animals are known to enter a hibernation-like state called brumation during transient cooling. However, the knowledge regarding the physiological responses of brumation is limited. Specifically, the impact of exposure to low-temperature conditions outside the range of temperature compensation on the subsequent circadian behavioral rhythms remains unclear. In this study, we investigated the effects of transient cooling on the behavioral circadian rhythm in the non-avian reptile, the bearded dragon (). Under constant light (LL) conditions at 30 °C, the animals exhibited a free-running rhythm, and exposure to low temperatures (4 °C) caused a complete cessation of locomotion. Furthermore, we revealed that the behavioral rhythm after rewarming is determined not by the circadian phase at the onset or the duration of cooling, but by the timing of cooling cessation.
动物在其自然生命周期中经常经历温度波动，包括低于其活动范围的低温期。例如，已知变温动物在短暂降温期间会进入一种类似冬眠的状态，称为冬蛰。然而，关于冬蛰生理反应的知识有限。具体而言，暴露于温度补偿范围之外的低温条件对随后的昼夜行为节律的影响仍不清楚。在本研究中，我们调查了短暂降温对非鸟类爬行动物鬃狮蜥行为昼夜节律的影响。在30°C的持续光照（LL）条件下，动物表现出自由运行节律，暴露于低温（4°C）会导致运动完全停止。此外，我们发现复温后的行为节律不是由降温开始时的昼夜相位或降温持续时间决定的，而是由降温停止的时间决定的。
