Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
Prog Brain Res. 2012;199:203-218. doi: 10.1016/B978-0-444-59427-3.00012-5.
Sleep is regulated by circadian and homeostatic processes. The sleep homeostat keeps track of the duration of prior sleep and waking and determines the intensity of sleep. In mammals, the homeostatic process is reflected by the slow waves in the non-rapid eye movement (NREM) sleep electroencephalogram (EEG). The circadian process is controlled by a pacemaker located in the suprachiasmatic nucleus of the hypothalamus and provides the sleep homeostat with a circadian framework. This review summarizes the changes in sleep obtained after different chronobiological interventions (changes in photoperiod, light availability, and running wheel availability), the influence of mutations or lesions in clock genes on sleep, and research on the interaction between sleep homeostasis and the circadian clock. Research in humans shows that the period of consolidated waking during the day is a consequence of the interaction between an increasing homeostatic sleep drive and a circadian signal, which promotes waking during the day and sleep during the night. In the rat, it was shown that, under constant homeostatic sleep pressure, with similar levels of slow waves in the NREM sleep EEG at all time points of the circadian cycle, still a small circadian modulation of the duration of waking and NREM sleep episodes was observed. Under similar conditions, humans show a clear circadian modulation in REM sleep, whereas in the rat, a circadian modulation in REM sleep was not present. Therefore, in the rat, the sleep homeostatic modulation in phase with the circadian clock seems to amplify the relatively weak circadian changes in sleep induced by the circadian clock. Knowledge about the interaction between sleep and the circadian clock and the circadian modulation of sleep in other species than humans is important to better understand the underlying regulatory mechanisms.
睡眠受昼夜节律和内稳态过程的调节。睡眠内稳态跟踪先前睡眠和清醒的持续时间，并确定睡眠的强度。在哺乳动物中，内稳态过程反映在非快速眼动 (NREM) 睡眠脑电图 (EEG) 的慢波中。昼夜节律过程由位于下丘脑视交叉上核的起搏器控制，并为睡眠内稳态提供昼夜节律框架。这篇综述总结了不同生物钟干预（光周期、光照可用性和跑步轮可用性的变化）后睡眠的变化、时钟基因的突变或损伤对睡眠的影响，以及睡眠内稳态和昼夜节律钟之间相互作用的研究。人类研究表明，白天巩固清醒的时间是不断增加的睡眠内稳态驱动力和促进白天清醒和夜间睡眠的昼夜节律信号相互作用的结果。在大鼠中，研究表明，在恒定的睡眠内稳态压力下，在昼夜节律周期的所有时间点，NREM 睡眠 EEG 中的慢波水平相似，仍然观察到清醒和 NREM 睡眠发作持续时间的微小昼夜节律调节。在相似的条件下，人类表现出明显的 REM 睡眠昼夜节律调节，而在大鼠中，没有 REM 睡眠的昼夜节律调节。因此，在大鼠中，与昼夜节律钟同步的睡眠内稳态调节似乎放大了昼夜节律钟诱导的睡眠中相对较弱的昼夜节律变化。了解睡眠与昼夜节律钟之间的相互作用以及其他物种（而非人类）的睡眠昼夜节律调节对于更好地理解潜在的调节机制非常重要。
