Light and food signals cooperate to entrain the rat pineal circadian system
Light and food signals cooperate to entrain the rat pineal circadian system
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DOI：
10.1002/jnr.21769
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发表时间：
2008-11
影响因子：
4.2
通讯作者：
Tao Wu;Yuanxiang Jin;H. Kato;Z. Fu
中科院分区：
文献类型：
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作者：
Tao Wu;Yuanxiang Jin;H. Kato;Z. Fu
光和食物信号分别是中枢和外周生物钟的两个主要授时器。然而，光和食物刺激的变化是否以及如何影响哺乳动物松果体时钟基因的昼夜节律仍然是未知的。在本研究中，我们首次建立了一种分析单个大鼠松果体中大多数时钟基因（Bmal 1，Per 1，Per 2，Per 3，Cry 1，Dec 1和Dec 2）和AANAT表达水平的方法，并利用该方法研究了摄食和光周期逆转对松果体昼夜节律系统的个体和协同效应。单独的摄食逆转（RF）7 d对松果体时钟基因表达的节律性只有微弱的影响，而在不改变摄食制度的情况下，相同时间段的光/暗逆转也不能完全逆转所有检测基因的表达时相。然而，LD周期的逆转与喂养制度一起完全抑制了松果体中的昼夜节律基因的表达在7天内。这些数据表明，光调节是比摄食相关线索更有效地调节松果体昼夜节律的主导线索，但食物的可获得性确实有助于松果体昼夜节律系统的再夹带。此外，RF在松果体昼夜节律系统中的无能表明松果体比其他外围器官更强烈地耦合到主时钟，并且在分层组织的哺乳动物昼夜节律系统中将其与其他外围器官区分开来。© 2008 Wiley利斯公司
Light and food signals are two dominant Zeitgeber for central and peripheral circadian clocks, respectively. However, whether and how changes in light and food stimuli affect circadian rhythms of mammalian pineal clock genes are still largely unknown. For the first time, in the present study, we established a method for analysis of the expression levels of most clock genes (Bmal1, Per1, Per2, Per3, Cry1, Dec1 and Dec2) and AANAT in a single rat pineal gland and used it to investigate individual and cooperative effects of feeding and light cycle reversals on the pineal circadian system. Feeding reversal (RF) alone for 7 days had only weak effect on the rhythmicity of clock gene expression in the pineal gland, whereas light/dark reversal for the same period without any change in the feeding regime could not absolutely reverse the expression phases of all examined genes either. However, reversal of the LD cycle together with the feeding regime completely resynchronized the circadian gene expression in the pineal gland within 7 days. These data suggest that photic regulation is the dominant cue that synchronizes the pineal circadian rhythm more efficiently than the feeding‐related cue, but food availability does contribute to reentrainment of the pineal circadian system. In addition, the inability of RF in the pineal circadian system suggests that the pineal gland is more strongly coupled to the master clock than other peripheral organs and alternatively distinguishes it from other peripheral organs in the hierarchically organized mammalian circadian systems. © 2008 Wiley‐Liss, Inc.