Shido O, Sakurada S, Fujikake K, Nagasaka T
Department of Physiology, School of Medicine, Kanazawa University, Japan.
Jpn J Physiol. 1993;43(5):685-96. doi: 10.2170/jjphysiol.43.685.
The effects of cold exposure for several hours at a fixed time once a day on nyctohemeral variations of hypothalamic temperature (Thy), heat balance, and feeding and locomotor activities were examined in rats. The cold-exposed group was subjected to an ambient temperature of 3 degrees C for about 5 h in the last half of the dark phase daily for 10 or more than 21 consecutive days, while the control rats were kept constant at 24 degrees C. The 10-d cold exposure had little effect on nyctohemeral changes in Thy and locomotor activity. However, after completing a 3- to 4-week cold exposure schedule, the levels of Thy, heat loss, heat production, and feeding and locomotor activities of the cold-exposed rats significantly decreased for 1-2 h during the period of the previous cold exposure time. These decreases lasted for at least 2 d after the end of the cold exposure schedule. These results suggest that the patterns of nyctohemeral changes in body core temperature and feeding and locomotor activities were altered after repeated cold exposure at a fixed time once a day in rats.
研究了大鼠每天在固定时间接受数小时冷暴露对其昼夜下丘脑温度（Thy）变化、热平衡以及进食和运动活动的影响。冷暴露组大鼠在每天黑暗期的后半段暴露于3摄氏度的环境温度下约5小时，持续10天或连续21天以上，而对照大鼠则保持在24摄氏度恒定温度。10天的冷暴露对Thy和运动活动的昼夜变化影响不大。然而，在完成3至4周的冷暴露方案后，冷暴露大鼠的Thy水平、热量散失、产热以及进食和运动活动在前冷暴露时间段内显著下降1至2小时。这些下降在冷暴露方案结束后至少持续2天。这些结果表明，大鼠每天在固定时间重复冷暴露后，其体核温度以及进食和运动活动的昼夜变化模式发生了改变。
