The Progression of Circadian Phase during Light Exposure in Animals and Humans
The Progression of Circadian Phase during Light Exposure in Animals and Humans
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DOI：
10.1177/0748730408330196
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发表时间：
2009-04-01
影响因子：
3.5
通讯作者：
Daan, Serge
中科院分区：
文献类型：
--
作者：
Beersma, Domien G. M.;Comas, Marian;Daan, Serge
对人类和小鼠的研究表明，光的昼夜节律相移效应在光暴露间隔开始时比在随后的暴露期间更大。关于这种反应减少现象的动力学知之甚少。在这里，作者提出了一种方法来获得信息的进展阶段在曝光。在很宽的持续时间范围内，对曝光间隔的相位响应曲线可用于肉蝇、小鼠和人类。通过比较不同持续时间的脉冲引起的相移，但在相同的昼夜节律相位开始，在长时间间隔（小时）的曝光期间的相位的进展重建这3个物种。对于苍蝇，相位进展曲线表明，光脉冲-如果足够长，最终使起搏器稳定在InT 18左右（接近主观黄昏），这是典型的强重置。相位向最终值的进展从未显示出大于7小时的提前，而延迟可以大至18小时。应用本文提出的相位进展曲线法，可以清楚地区分0型相位响应曲线的超前和滞后。在肉蝇（Sarcophaga）中，延迟和提前之间的分歧发生在光照开始于InT 0（主观午夜）时。目前的研究证实了早期在小鼠身上的发现，即光脉冲的开始比随后几个小时的光产生更强的相移。反应降低在暴露后1小时内完成。有人认为，这种变化是不是由于光适应过程，而是响应饱和。与光适应相反，反应饱和是自然夹带期间昼夜节律起搏器正常运作的基础。为了理解起搏器对自然光的夹带，应用自然光剖面的相位进展曲线可能是一个重要的工具。
Studies in humans and mice revealed that circadian phase shifting effects of light are larger at the beginning of a light exposure interval than during subsequent exposure. Little is known about the dynamics of this response reduction phenomenon. Here the authors propose a method to obtain information on the progression of phase during light exposure. Phase response curves to intervals of light exposure over a wide range in duration are available for flesh flies, mice, and humans. By comparing the phase shifts induced by pulses of various durations but starting at the same circadian phase, the progression of phase during a long interval (hours) of light exposure is reconstructed for each of these 3 species. For flies, the phase progression curves show that light pulses-if long enough eventually make the pacemaker stabilize around InT18 (near subjective dusk), as is typical for strong resetting. The progression of phase toward the final value never shows advances larger than 7 h, while delays can be as large as 18 h. By applying the phase progression curve method presented in this study, differences between advances and delays in type-0 phase response curves can be distinguished clearly. In flesh flies (Sarcophaga) this bifurcation between delays and advance occurs when light exposure starts at InT0 (subjective midnight). The present study confirms earlier findings in mice showing that the beginning of the light pulse generates stronger phase shifts than subsequent hours of light. Response reduction is complete within 1 h of exposure. It is argued that the variation is not so much due to light adaptation processes, but rather to response saturation. In contrast to light adaptation, response saturation is fundamental to proper functioning of the circadian pacemaker during natural entrainment. For understanding entrainment of the pacemaker to natural light, phase progression curves in which naturalistic light profiles are applied could be an important tool.