Jet-lag symptoms arise from temporal misalignment between the internal circadian clock and external solar time when traveling across multiple time zones. Light is known as a strong timing cue of the circadian clock. We here examined the effect of daily light on the process of jet lag by detecting c-Fos expression in the master clock neurons in the suprachiasmatic nucleus (SCN) under 8-hr phase-advanced jet lag condition. In WT mice, c-Fos-immunoreactivity was found at 1-2 hours on the first day after light/dark (LD) phase-advance. This induction was also observed on the second and third days, although their levels were diminished day by day. In contrast, c-Fos induction in the SCN of V1a-/-V1b-/- mice, which show virtually no jet lag symptoms even after 8-hr phase-advance, was only detected on the first day. These results indicate that external light has affected SCN neuronal activity for 3 days after LD phase-advance in WT mice suggesting the continuous progress of activity change of SCN neurons under jet lag conditions. Noteworthy, limited c-Fos induction in V1a-/-V1b-/- SCN is also consistent with the rapid reentrainment of the SCN clock in mutant mice after 8-hr LD phase-advance.

中文翻译：

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日射流对时滞条件下视交叉上核中c-Fos表达的影响。

时差症状是由于在多个时区旅行时，内部生物钟与外部太阳时间之间的时间未对准而引起的。光线被称为昼夜节律时钟的强大计时提示。在这里，我们通过检测8小时相差时延滞后条件下视交叉上核（SCN）主时钟神经元中c-Fos的表达来检查日光对时滞过程的影响。在野生型小鼠中，c / Fos免疫反应性在明/暗（LD）阶段提前后的第一天的1-2小时发现。在第二天和第三天也观察到这种诱导，尽管它们的水平每天都在降低。相反，仅在第一天就检测到了V1a-/-V1b-/-小鼠SCN中的c-Fos诱导，即使在提前8小时后实际上也没有显示时差症状。这些结果表明，外源光影响了WT小鼠LD阶段前进后3天的SCN神经元活性，表明在时差反应条件下SCN神经元的活性变化持续不断。值得注意的是，在V1a-/-V1b-/-SCN中有限的c-Fos诱导也与8小时LD相位提前后突变小鼠中SCN时钟的快速重新夹带一致。