Reebs S G, St-Coeur J
Département de Biologie, Université de Moncton, Canada.
Physiol Behav. 1994 Jun;55(6):1113-7. doi: 10.1016/0031-9384(94)90395-6.
This study examined whether a nonphotic factor, scheduled daily exercise, could cause aftereffects on the free-running circadian period of Syrian hamsters. Groups of hamsters were kept under a cycle of 14-h light:10-h dark with access to their running wheel for only 3 h a day. Depending on the group, this 3-h period coincided with early day, midday, late day, early night, or late night. Controls did not have access to wheels. After 12 days, all hamsters were released into constant darkness (DD) and given free access to their wheel. Late-day runners showed a significantly shorter free-running period in DD compared to night runners and to controls, indicating that free-running periods can be shortened by nonphotic factors in this species. On the first day of DD, the activity onset of hamsters preceded (midday and late-day runners), coincided with (night runners and controls), or followed (early day runners) the previous time of D onset. Advanced activity onsets in late-day runners were consistent with both their short free-running periods and probable phase-advancing effects of late-day exercise; in contrast, delayed activity onsets in early day runners could only be explained by phase-delaying effects of the scheduled exercise.
本研究考察了一种非光因素——每日定时锻炼，是否会对叙利亚仓鼠的自由运行昼夜节律周期产生后效应。将仓鼠分组，置于14小时光照：10小时黑暗的周期环境中，每天仅允许它们使用跑轮3小时。根据组别不同，这3小时分别安排在清晨、中午、傍晚、深夜或午夜。对照组仓鼠没有跑轮可用。12天后，所有仓鼠被置于持续黑暗（DD）环境中，并可自由使用跑轮。与夜间跑步的仓鼠和对照组相比，傍晚跑步的仓鼠在DD环境中的自由运行周期显著更短，这表明该物种的自由运行周期可被非光因素缩短。在DD环境的第一天，仓鼠的活动起始时间在之前光照开始时间之前（中午和傍晚跑步的仓鼠）、与之重合（夜间跑步的仓鼠和对照组）或之后（清晨跑步的仓鼠）。傍晚跑步的仓鼠活动起始时间提前，这与它们较短的自由运行周期以及傍晚锻炼可能产生的相位提前效应均相符；相比之下，清晨跑步的仓鼠活动起始时间延迟，这只能用定时锻炼产生的相位延迟效应来解释。
