Phase and period responses of the circadian system of mice (Mus musculus) to light stimuli of different duration
Phase and period responses of the circadian system of mice (Mus musculus) to light stimuli of different duration
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DOI：
10.1177/0748730406292446
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发表时间：
2006-10-01
影响因子：
3.5
通讯作者：
Daan, S.
中科院分区：
文献类型：
--
作者：
Comas, M.;Beersma, D. G. M.;Daan, S.
为了了解昼夜节律系统对自然界中不同光周期的影响，了解不同持续时间的单光脉冲对自由运行系统的影响是很重要的。作者研究了实验室小鼠（C57BL6J//OlaHsd）对7种不同持续时间（1、3、4、6、9、12和18小时）的单光脉冲（每11天一次）的相位和周期反应。光脉冲持续时间对相位响应曲线的幅值和形状都有影响。9小时光脉冲产生最大振幅PRC。与其他系统一样，昼夜节律周期随延迟而略微延长，随提前而缩短。作者的目的是了解光信号的不同部分如何导致最终的相移。当使用脉冲的起始点、中点和结束点作为相位参考来绘制prc时，使用中脉冲时它们之间的对应关系最好。使用一个简单的纯相位模型，作者探索了光在脉冲的第一个小时内强烈影响振荡器速度的可能性，并且由于光感受器的适应，光在脉冲的后几个小时内强度降低。他们将基于1小时PRC的模型拟合到所有光脉冲的数据中。当第1小时后的所有小时的光效应相对于第1小时降低0.22倍时，各prc之间的总体对应关系最佳。对于预测的prc，光作用平均集中在光脉冲的38%。这是接近参考相位产生最佳对应的脉冲的36%。因此，该结果与光脉冲开始的初始主要贡献相一致，随后光的影响减少，导致不同持续时间脉冲的prc之间的差异。作者认为，在绘制和比较不同光脉冲持续时间的prc时，中脉冲是比开灯更好的相位参考。
To understand entrainment of circadian systems to different photoperiods in nature, it is important to know the effects of single light pulses of different durations on the free-running system. The authors studied the phase and period responses of laboratory mice (C57BL6J//OlaHsd) to single light pulses of 7 different durations (1, 3, 4, 6, 9, 12, and 18 h) given once per 11 days in otherwise constant darkness. Light-pulse duration affected both amplitude and shape of the phase response curve. Nine-hour light pulses yielded the maximal amplitude PRC. As in other systems, the circadian period slightly lengthened following delays and shortened following advances. The authors aimed to understand how different parts of the light signal contribute to the eventual phase shift. When PRCs were plotted using the onset, midpoint, and end of the pulse as a phase reference, they corresponded best with each other when using the mid-pulse. Using a simple phase-only model, the authors explored the possibility that light affects oscillator velocity strongly in the 1st hour and at reduced strength in later hours of the pulse due to photoreceptor adaptation. They fitted models based on the 1-h PRC to the data for all light pulses. The best overall correspondence between PRCs was obtained when the effect of light during all hours after the first was reduced by a factor of 0.22 relative to the 1st hour. For the predicted PRCs, the light action centered on average at 38% of the light pulse. This is close to the reference phase yielding best correspondence at 36% of the pulses. The result is thus compatible with an initial major contribution of the onset of the light pulse followed by a reduced effect of light responsible for the differences between PRCs for different duration pulses. The authors suggest that the mid-pulse is a better phase reference than lights-on to plot and compare PRCs of different light-pulse durations.