Circadian Rhythm Laboratory, University of South Carolina, 807 Hampton Street, Walterboro, SC 29488, USA.
J Biol Rhythms. 2010 Aug;25(4):247-56. doi: 10.1177/0748730410372074.
Much is known about how environmental light-dark cycles synchronize circadian rhythms in animals. The ability of environmental cycles of ambient temperature to synchronize circadian rhythms has also been investigated extensively but mostly in ectotherms. In the present study, the synchronization of the circadian rhythm of running-wheel activity by environmental cycles of ambient temperature was studied in laboratory mice. Although all mice were successfully entrained by a light-dark cycle, only 60% to 80% of the mice were entrained by temperature cycles (24-32 degrees C or 24-12 degrees C), and attainment of stable entrainment seemed to take longer under temperature cycles than under a light-dark cycle. This suggests that ambient temperature cycles are weaker zeitgebers than light-dark cycles, which is consistent with the results of the few previous studies using mammalian species. Whereas 80% of the mice were entrained by 24-h temperature cycles, only 60% were entrained by 23-h cycles, and none was entrained by 25-h cycles. The results did not clarify whether entrainment by temperature cycles is caused directly by temperature or indirectly through a temperature effect on locomotor activity, but it is clear that the rhythm of running-wheel activity in mice can be entrained by ambient temperature cycles in the nonnoxious range.
关于环境光-暗周期如何使动物的生物钟同步，人们已经了解很多。环境温度周期使生物钟同步的能力也已经被广泛研究，但主要是在变温动物中。在本研究中，环境温度周期对实验小鼠跑步轮活动的生物钟同步进行了研究。虽然所有的老鼠都成功地被光-暗周期所驯化，但只有 60%到 80%的老鼠被温度周期（24-32°C 或 24-12°C）所驯化，而且在温度周期下达到稳定驯化似乎比在光-暗周期下需要更长的时间。这表明环境温度周期是比光-暗周期较弱的授时因子，这与使用哺乳动物物种的少数先前研究的结果一致。虽然 80%的老鼠被 24 小时温度周期驯化，但只有 60%的老鼠被 23 小时周期驯化，没有老鼠被 25 小时周期驯化。结果并不能明确温度周期的驯化是直接由温度引起的，还是通过温度对运动活动的影响间接引起的，但很明显，老鼠跑步轮活动的节律可以被环境温度周期在非有害范围内驯化。
