Plasticity of circadian behavior and the suprachiasmatic nucleus following exposure to non-24-hour light cycles
Plasticity of circadian behavior and the suprachiasmatic nucleus following exposure to non-24-hour light cycles
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DOI：
10.1177/0748730404264156
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发表时间：
2004-06-01
影响因子：
3.5
通讯作者：
Herzog, ED
中科院分区：
文献类型：
--
作者：
Aton, SJ;Block, GD;Herzog, ED
周期后效区域形式的行为可塑性，其中昼夜节律行为的自由运行期经历经验依赖性的变化。目前还不清楚这种可塑性是否是年龄依赖性的，以及行为周期的变化是否与SCN或视网膜的变化有关，这是哺乳动物中已知的昼夜节律起搏器。为了确定这些变化是否随年龄而变化，将不同年龄的Per 1-luc转基因小鼠（其中荧光素酶基因由Period 1启动子驱动）暴露于短（10 h光照：10 h黑暗，T20）或长（14 h光照：14 h黑暗，T28）光照周期（T周期）。在恒定黑暗（DD）中的转轮活动记录显示，T20小鼠的固有周期显着短于T28小鼠在所有年龄。在3个月以上的小鼠中，较短的光周期后的后效显著较小，对应于夹带到T20的能力降低。年龄并没有减少夹带或后效在28小时光照时间表。在DD出生的幼崽的行为周期依赖于在子宫内经历的T周期，表现出后效的母体转移。离体SCN的Per 1-luc活性测定结果显示，幼龄小鼠SCN有一定的后效，但行为周期与SCN呈负相关。眼球摘除对DD的行为后效应没有影响，表明后效应的表达不需要眼睛。这些数据表明，昼夜节律后效是一种年龄依赖性形式的可塑性介导的稳定变化的SCN，重要的是，外SCN组织。
Period aftereffects area form of behavioral plasticity in which the free-running period of circadian behavior undergoes experience-dependent changes. It is unclear whether this plasticity is age dependent and whether the changes in behavioral period relate to changes in the SCN or the retina, 2 known circadian pacemakers in mammals. To determine whether these changes vary with age, Per1-luc transgenic mice (in which the luciferase gene is driven by the Period1 promoter) of different ages were exposed to short (10 h light: 10 h dark, T20) or long (14 h light: 14 h dark, T28) light cycles (T cycles). Recordings of running-wheel activity in constant darkness (DD) revealed that the intrinsic periods of T20 mice were significantly shorter than of T28 mice at all ages. Aftereffects following the shorter light cycle were significantly smaller in mice older than 3 months, corresponding with a decreased ability to entrain to T20. Age did not diminish entrainment or aftereffects in the 28-h light schedule. The behavioral period of pups born in DD depended on the T cycle experienced in utero, showing maternal transference of aftereffects. Recordings of Per1-luc activity from the isolated SCN in vitro revealed that the SCN of young mice expressed aftereffects, but the periods of behavior and SCN were negatively correlated. Enucleation in DD had no effect on behavioral aftereffects, indicating the eyes are not required for aftereffects expression. These data show that circadian aftereffects are an age-dependent form of plasticity mediated by stable changes in the SCN and, importantly, extra-SCN tissues.