Temporal and spatial distribution of immunoreactive PER1 and PER2 proteins in the suprachiasmatic nucleus and peri-suprachiasmatic region of the diurnal grass rat (Aruicanthis niloticus)
Temporal and spatial distribution of immunoreactive PER1 and PER2 proteins in the suprachiasmatic nucleus and peri-suprachiasmatic region of the diurnal grass rat (Aruicanthis niloticus)
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DOI：
10.1016/j.brainres.2005.11.082
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发表时间：
2006-02-16
期刊：
影响因子：
2.9
通讯作者：
Smale, L
中科院分区：
文献类型：
--
作者：
Ramanathan, C;Nunez, AA;Smale, L
在昼行性和夜行性哺乳动物中，下丘脑的视交叉上核（SCN）包含主要的昼夜节律起搏器。紧靠SCN的下室旁带（LSPV）也可能在调节昼夜节律中发挥重要作用。SCN包含大量振荡细胞，这些振荡细胞通过转录/翻译反馈回路产生昼夜节律，这些反馈回路涉及一组时钟基因，包括per1和per2。在白天活动的哺乳动物中，这些基因编码的蛋白质的时间和空间特征知之甚少。本研究的第一个目的是表征无条纹尼罗河草鼠（Arvicanthis niloticus）的SCN中PER1和PER2的表达。第二个目的是评估LSPV中可能存在分子钟的假设，其中Fos表达的内源性节律在草地大鼠中可见，而在实验室大鼠中没有。将动物置于12:12的明暗循环中，每隔4小时灌注一次，对其大脑进行PER1和PER2的免疫组化检测。这两种蛋白都在SCN中被发现，它们在黑暗期的早期达到峰值，这进一步证明了昼夜行为模式的差异来自于SCN内起搏器下游的机制。PER1和PER2的节律性表达也在LSPV中被发现，这为该区域可能参与草鼠昼夜节律时间保持的假设提供了支持。此外，在LSPV和SCN外侧可见节律。根据昼夜活动动物昼夜节律计时系统的异同，讨论了本研究的结果。(c) 2005 Elsevier B.V.版权所有
The suprachiasmatic nucleus (SCN) of the hypothalamus contains the primary circadian pacemaker in both diurnal and nocturnal mammals. The lower subparaventricular zone (LSPV) immediately dorsal to the SCN may also play an important role in the regulation of circadian rhythms. The SCN contains a multitude of oscillator cells that generate circadian rhythms through transcriptional/translational feedback loops involving a set of clock genes including per1 and per2. Little is known about the temporal and spatial features of the proteins encoded by these genes in day-active mammals. The first objective of this study was to characterize the expression of PER1 and PER2 in the SCN of a diurnal rodent, the unstriped Nile grass rat (Arvicanthis niloticus). The second objective was to evaluate the hypothesis that a molecular clock could exist in the LSPV, where endogenous rhythms in Fos expression are seen in grass rats but not in laboratory rats. Animals were kept on a 12:12 light/dark cycle and perfused at 4-h intervals, and their brains were processed for immunohistochemical detection of PER1 and PER2. Both proteins were seen in the SCN where they peaked early in the dark phase, providing further evidence that the differences between diurnal and nocturnal patterns of behavior emerge from mechanisms lying downstream from the pacemaker within the SCN. Rhythmic expression of PER1 and PER2 was also seen in the LSPV providing support for the hypothesis that this region might participate in circadian time keeping in the diurnal grass rat. In addition, rhythms were seen lateral to the LSPV and the SCN. Results of this study are discussed in light of similarities and differences in the circadian time-keeping systems of day- and night-active animals. (c) 2005 Elsevier B.V. All rights reserved.