Division of Neurotoxicology, National Center for Toxicological Research/FDA, United States.
Physiol Behav. 2013 Jul 2;119:130-6. doi: 10.1016/j.physbeh.2013.06.007. Epub 2013 Jun 13.
The existence of seasonal or circannual effects on laboratory rodent behavior has been the subject of much debate in recent conversations with colleagues. If such effects are real, they could explain poor replicability or hinder the detection of treatment effects. Here, we review the literature in which seasonal or circannual rhythms were examined under typical 12:12h photoperiods and present our historical data of locomotor activity of male and female Sprague-Dawley rats across several seasons and years. In general, there was little evidence to indicate significant effects on the locomotor activity of rats or mice, while studies of depression behaviors were somewhat inconsistent in their findings. Results of the few anxiety behavior assessments were fairly consistent, at least in rat studies. Two studies of pain-related behaviors indicated decreased responses during spring or summer testing. If such seasonal effects are real, this would imply that laboratory rodents have a type of internal Type 2 circannual clock or endogenous oscillator. However, photoperiod, temperature, or humidity cannot be the zeitgeber. Further, the need for a circannual clock in a short-lived rodent is debatable.
实验室啮齿动物行为的季节性或年周期效应的存在，是近期与同事交流中备受争议的话题。如果这些效应确实存在，它们可能会导致较差的可重复性或阻碍治疗效果的检测。在这里，我们回顾了在典型的 12:12h 光周期下检查季节性或年周期节律的文献，并呈现了我们关于雄性和雌性 Sprague-Dawley 大鼠在多个季节和年份的运动活动的历史数据。总的来说，几乎没有证据表明对大鼠或小鼠的运动活动有显著影响，而抑郁行为的研究结果在其发现上有些不一致。少数焦虑行为评估的结果相当一致，至少在大鼠研究中是如此。两项与疼痛相关行为的研究表明，春季或夏季测试时反应减弱。如果这种季节性效应确实存在，这将意味着实验啮齿动物具有一种内部的 2 型年周期时钟或内源性振荡器。然而，光周期、温度或湿度不可能是授时因子。此外，短寿命啮齿动物是否需要年周期时钟是值得商榷的。
