van Dorp Rick, Deboer Tom
Laboratory of Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands.
J Biol Rhythms. 2025 Feb;40(1):62-75. doi: 10.1177/07487304241302547. Epub 2024 Dec 18.
Environmental light conditions during development can have long-lasting effects on the physiology and behavior of an animal. Photoperiod, a clear example of environmental light conditions, is detected by and coded in the suprachiasmatic nucleus. It is therefore possible that differences observed in behavior in adulthood after exposure to different perinatal photoperiods are caused by lasting changes in the suprachiasmatic nucleus or alternatively, in other nuclei affected by perinatal photoperiod. It can then be expected that behavior with strong circadian aspects, like rest-activity and sleep, are affected by difference in photoperiod during development as well. To investigate this further, we exposed mice to different photoperiods during their development in the womb until weaning (long: 16 h of light, 8 h of darkness; short: 8 h of light, 16 h of darkness). After weaning, the animals were exposed to a 12 h:12 h light:dark cycle for at least 3 more weeks and some animals were subsequently exposed to constant darkness. We assessed their rest-activity patterns by recording voluntary locomotor activity and used EEG recordings to determine sleep architecture and electroencephalographic spectral density. Perinatal long photoperiod animals showed a shorter duration of locomotor activity than short photoperiod-developed mice in a 12:12 light-dark cycle. This difference disappeared in constant darkness. In the light phase, that is, during the day, perinatal long photoperiod mice spent less time awake and more time in NREM sleep than short photoperiod-developed mice. No effects of perinatal photoperiod were observed in the EEG spectral density or in response to sleep deprivation. We see lasting differences in behavioral locomotor activity and sleep in female and male mice after exposure to different perinatal photoperiods. We conclude that perinatal photoperiod programs a developing mammal for different external conditions and changes brain physiology, which in turn results in long-lasting, possibly even permanent, changes in the sleep and locomotor activity.
发育过程中的环境光照条件会对动物的生理和行为产生长期影响。光周期作为环境光照条件的一个明显例子，由视交叉上核检测并编码。因此，在暴露于不同围产期光周期后成年期观察到的行为差异，可能是由视交叉上核的持久变化引起的，或者是由受围产期光周期影响的其他核团的变化引起的。那么可以预期，具有强烈昼夜节律特征的行为，如休息 - 活动和睡眠，也会受到发育过程中光周期差异的影响。为了进一步研究这一点，我们在小鼠子宫内发育直至断奶期间将其暴露于不同的光周期（长：16小时光照，8小时黑暗；短：8小时光照，16小时黑暗）。断奶后，动物至少再暴露于12小时：12小时光：暗循环3周，随后一些动物暴露于持续黑暗中。我们通过记录自主运动活动来评估它们的休息 - 活动模式，并使用脑电图记录来确定睡眠结构和脑电图频谱密度。在12:12光 - 暗循环中，围产期长光周期动物的运动活动持续时间比短光周期发育的小鼠短。这种差异在持续黑暗中消失。在光照阶段，即白天，围产期长光周期小鼠比短光周期发育的小鼠清醒时间少，非快速眼动睡眠时间多。在脑电图频谱密度或对睡眠剥夺的反应中未观察到围产期光周期的影响。我们发现，在暴露于不同围产期光周期后，雌性和雄性小鼠的行为运动活动和睡眠存在持久差异。我们得出结论，围产期光周期为发育中的哺乳动物设定了适应不同外部条件的程序，并改变了大脑生理，进而导致睡眠和运动活动的长期甚至可能是永久性的变化。
