Perret M, Aujard F
Laboratoire d'Ecologie Générale, UMR 8571, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, F-91800 Brunoy, France.
Am J Physiol Regul Integr Comp Physiol. 2001 Dec;281(6):R1925-33. doi: 10.1152/ajpregu.2001.281.6.R1925.
To study the temporal organization of daily hypothermia and torpor in a nocturnal Malagasy primate, the gray mouse lemur, body temperature (T(b)) and locomotor activity were recorded using telemetry on 39 males held in 24-h light-dark cycles of different photoperiods. Under free-running condition, the circadian T(b) and locomotor activity rhythms had a period shorter than 24 h. Circadian daily hypothermia started by a rapid drop in T(b) (0.24 degrees C/10 min) at the end of subjective night (13 h 25 +/- 20 min) and was characterized by minimal T(b) values 3 h 20 +/- 5 min later. Spontaneous arousal from daily hypothermia occurred at a fixed time (6 h 05 +/- 15 min, n = 7) after the beginning of subjective day. In animals exposed to 24-h light-dark cycles with night duration varying from 10 to 14 h, locomotor activity was strictly restricted to dark time, but the temporal organization of daily hypothermia was not modified, although changes in amplitude of T(b) rhythm were observed. Daily hypothermia was directly induced by light and lasted 5 h 10 +/- 10 min, with minimal T(b) values 3 h 30 +/- 30 min (n = 28) after lights on, on condition that nighttime did not exceed the duration of subjective night. However, in animals exposed to 24-h light-dark cycles with night duration varying from 10 to 5 h, the limit of induction of daily hypothermia by light was ~9 h after the beginning of night. Finally, under short days (14:10-h light-dark cycle), long bouts (6 h 50 +/- 40 min) of actual torpor (minimum T(b) 27.6 +/- 0.9 degrees C) were observed and would involve mechanisms depending on physiological changes induced by short day exposure.
为研究马达加斯加夜行性灵长类动物灰鼠狐猴每日体温过低和蛰伏的时间组织，利用遥测技术记录了处于不同光周期的24小时明暗循环中的39只雄性灰鼠狐猴的体温（T(b)）和运动活动。在自由运行条件下，昼夜体温（T(b)）和运动活动节律的周期短于24小时。昼夜性每日体温过低始于主观夜间结束时体温（T(b)）的快速下降（0.24℃/10分钟），其特征是3小时20分钟±5分钟后体温（T(b)）达到最低值。每日体温过低后的自发苏醒发生在主观白天开始后的固定时间（6小时05分钟±15分钟，n = 7）。在暴露于夜间时长从10小时到14小时变化的24小时明暗循环的动物中，运动活动严格限制在黑暗时间，但尽管观察到体温（T(b)）节律幅度的变化，每日体温过低的时间组织并未改变。每日体温过低由光照直接诱导，持续5小时10分钟±10分钟，开灯后3小时30分钟±30分钟达到最低体温（T(b)）值（n = 28），条件是夜间时长不超过主观夜间时长。然而，在暴露于夜间时长从10小时到5小时变化的24小时明暗循环的动物中，光照诱导每日体温过低的极限是夜间开始后约9小时。最后，在短日照（14:10小时明暗循环）条件下，观察到长时间（6小时50分钟±40分钟）的实际蛰伏（最低体温（T(b)）27.6℃±0.9℃），这可能涉及取决于短日照暴露引起的生理变化的机制。
