"Feeding time" for the brain: A matter of clocks
"Feeding time" for the brain: A matter of clocks
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DOI：
10.1016/j.jphysparis.2007.05.002
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发表时间：
2006-11-01
影响因子：
--
通讯作者：
Challet, Etienne
中科院分区：
文献类型：
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作者：
Feillet, Celine A.;Albrecht, Urs;Challet, Etienne
生物钟是一种自主的计时机制，允许生物体预测和适应光，温度和食物供应的环境节奏。在分子水平上，生物钟利用生物钟和生物钟控制的基因来产生节律和分配时间信号。在哺乳动物中，位于下丘脑视交叉上核的主生物钟的同步主要是通过光刺激来完成的。用餐时间可以通过实验方式通过时间限制进食来调节，它是外围振荡器的有效同步器，对视交叉上时钟没有明显的同步影响。此外，食物限制的动物能够预测进餐时间，如运动活动、体温和血浆皮质酮的预期发作所揭示的。这些食物预期节律一直被认为是在食物进入时钟（FEC）的控制下。对生物钟突变小鼠的分析强调了一些（但不是所有）生物钟基因与食物可消化的钟表装置的相关性。Clock或Per1的突变不会损害食物预期成分的表达，这表明这些时钟基因对于食物可消化的振荡不是必需的。相比之下，Npas2突变或Cry1和Cry2缺陷的小鼠对限制性喂养条件的反应或多或少发生了改变。此外，缺乏食物预期与Pert的突变特别相关，这表明该基因在预期用餐时间中的关键参与。FEC的实际位置尚未明确界定。尽管如此，目前的知识，假定的大脑区域参与食物可消化的振荡进行了讨论。我们还描述了几种神经化学途径，包括食欲素能和去甲肾上腺素能，可能参与传递输入和输出的FEC控制预期的过程。(c)2007爱思唯尔有限公司保留所有权利。
Circadian clocks are autonomous time-keeping mechanisms that allow living organisms to predict and adapt to environmental rhythms of light, temperature and food availability. At the molecular level, circadian clocks use clock and clock-controlled genes to generate rhythmicity and distribute temporal signals. In mammals, synchronization of the master circadian clock located in the suprachiasmatic nuclei of the hypothalamus is accomplished mainly by light stimuli. Meal time, that can be experimentally modulated by temporal restricted feeding, is a potent synchronizer for peripheral oscillators with no clear synchronizing influence on the suprachiasmatic clock. Furthermore, food-restricted animals are able to predict meal time, as revealed by anticipatory bouts of locomotor activity, body temperature and plasma corticosterone. These food anticipatory rhythms have long been thought to be under the control of a food-entra-inable clock (FEC). Analysis of clock mutant mice has highlighted the relevance of some, but not all of the clock genes for food-entrainable clockwork. Mutations of Clock or Per1 do not impair expression of food anticipatory components, suggesting that these clock genes are not essential for food-entrainable oscillations. By contrast, mice mutant for Npas2 or deficient for Cry1 and Cry2 show more or less altered responses to restricted feeding conditions. Moreover, a lack of food anticipation is specifically associated with a mutation of Pert, demonstrating the critical involvement of this gene in the anticipation of meal time. The actual location of the FEC is not yet clearly defined. Nevertheless, current knowledge of the putative brain regions involved in food-entrainable oscillations is discussed. We also describe several neurochemical pathways, including orexinergic and noradrenergic, likely to participate in conveying inputs to and outputs from the FEC to control anticipatory processes. (c) 2007 Elsevier Ltd. All rights reserved.