Department of Anatomy, Medical School, University of Pécs, Hungary.
Gen Comp Endocrinol. 2011 May 15;172(1):170-2. doi: 10.1016/j.ygcen.2011.01.012. Epub 2011 Feb 1.
Shift workers have a higher risk of metabolic syndrome, a condition that also develops in mice carrying mutation in their circadian clock gene clock. To collect more data on the transcriptional changes of clock under phase-shifted light/dark LD conditions, we examined the 24h patterns of clock mRNA expression in vivo and in vitro in chickens exposed acutely to a reversed LD (DL) cycle. Under controlled LD conditions (lights on at 6:00, lights off at 20:00), clock mRNA expression peaked in vivo at 2:00 (Zeitgeber Time 20, ZT20) and in vitro at 22:00 (ZT16). Even higher mRNA contents were measured in the first cycle of in vivo DL conditions between 22:00 and 6:00 (lights at night), but in the second cycle by 2:00, lower mRNA contents were detected than the control peak values seen at this time point. Furthermore, no alterations were found in vitro in clock mRNA content during the first 12h of DL conditions (lights at night). The differences seen between the first and the second DL cycles in vivo and between the in vivo and in vitro data for the first DL cycle support the idea that neurohumoral signals perturbed by a phase-delayed light-dark cycle may also play a role in the in vivo rapid transcriptional resetting of the circadian clock in the chicken pineal model.
轮班工作的人患代谢综合征的风险更高，而这种疾病也会发生在其生物钟基因 clock 发生突变的老鼠身上。为了收集更多关于生物钟在光/暗相移 LD 条件下转录变化的信息，我们检查了在急性暴露于反转 LD（DL）周期的鸡体内和体外生物钟 mRNA 表达的 24 小时模式。在受控 LD 条件下（6:00 开灯，20:00 关灯），生物钟 mRNA 表达在体内峰值出现在 2:00（时间生物标记 20，ZT20），在体外峰值出现在 22:00（ZT16）。即使在体内 DL 条件的第一个周期（夜间开灯）中测量到的 mRNA 含量更高，但在第二个周期的 2:00 时，检测到的 mRNA 含量低于此时点的对照峰值。此外，在 DL 条件的前 12 小时（夜间开灯），体外生物钟 mRNA 含量没有变化。体内的第一个和第二个 DL 周期之间以及体内和体外第一个 DL 周期的数据之间的差异表明，被相移的光-暗周期扰乱的神经激素信号也可能在鸡松果体模型中生物钟的快速转录重置中发挥作用。
