Photic entrainment and induction of immediate-early genes within the rat circadian system
Photic entrainment and induction of immediate-early genes within the rat circadian system
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DOI：
10.1016/s0006-8993(99)01073-2
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发表时间：
1999-03-06
期刊：
影响因子：
2.9
通讯作者：
Amir, S
中科院分区：
文献类型：
--
作者：
Beaulé, C;Amir, S
即刻早期基因(IEGs)在啮齿动物的昼夜节律系统中瞬时表达，对夜间光照做出反应。在这个系统中，研究最多的两个光诱导IEG是Fos和Jun-B。这两个基因在下丘脑视交叉上核(SCN)的分子表达与光诱导的行为相移相关。以前关于Fos和Jun-B在生物钟重置中作用的研究使用了能引起强烈相移的光刺激。然而，在大鼠中，SCN中Fos和Jun-B的表达与光诱导的相移之间的关系尚未见文献记载。在本研究中，确定自由跑周期的雄性大鼠被带到0.5h：23.5h的LD周期中。在稳定夹带的第15天，夹带光脉冲减少到10min。50min后处死动物，取脑进行IEG免疫细胞化学染色。在SCN和膝间小叶(IGL)有较强的Fos诱导。Jun-B仅见于SCN，而Jun-B在IGL中的标记较弱。在SCN中光诱导的IEG的大小与稳定携带到0.5h：23.5h LD周期所需的每日相移的大小之间获得了显著的相关性。此外，在SCN和IGL中，Fos和Jun-B免疫反应细胞数之间存在显著的相关性。这些数据表明，SCN内Fos和Jun-B诱导的大小与稳定夹带所需的每日相移的大小有关。(C)1999 Elsevier Science B.V.保留所有权利。
Immediate-early genes (IEGs) are transiently expressed within the rodent circadian system in response to nocturnal light. The two most studied light-induced IEGs within this system are Fos and Jun-B. Molecular expression of these two genes within the hypothalamic suprachiasmatic nucleus (SCN) correlates with light-induced behavioral phase shifts. Previous studies of the role of Fos and Jun-B in circadian clock resetting have used light stimuli that induce strong phase shifts. However, the relationship of Fos and Jun-B expression in the SCN and light-induced phase shifts in an entrainment context is undocumented in rats. In this study, male rats for which the free running period was determined were entrained to a 0.5 h:23.5 h LD cycle. On the fifteenth day of stable entrainment, the entraining light pulse was reduced to 10 min. Animals were killed 50 min later and brains were processed for IEG immunocytochemistry. Strong Fos induction was observed in the SCN and the intergeniculate leaflet (IGL). Strong Jun-B immunoreactivity was observed only in the SCN whereas Jun-B labeling in the IGL was weak. Significant correlations were obtained between the magnitude of light-induced IEGs in the SCN and the magnitude of the daily phase shift required for stable entrainment to the 0.5 h:23.5 h LD cycle. Further, a significant correlation was observed between the number of Fos and Jun-B immunoreactive cells in the SCN and IGL. These data suggest that the magnitude of Fos and Jun-B induction within the SCN is related to the magnitude of the daily phase shift required for stable entrainment. (C) 1999 Elsevier Science B.V. All rights reserved.