The circadian pacemaker in the cultured suprachiasmatic nucleus from pup mice is highly sensitive to external perturbation
The circadian pacemaker in the cultured suprachiasmatic nucleus from pup mice is highly sensitive to external perturbation
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DOI：
10.1111/j.1460-9568.2008.06231.x
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发表时间：
2008-05-01
影响因子：
3.4
通讯作者：
Honma, Ken-ichi
中科院分区：
文献类型：
--
作者：
Nishide, Shin-ya;Honma, Sato;Honma, Ken-ichi
下丘脑视交叉上核（SCN）中的昼夜节律钟在啮齿动物的胎儿和新生儿时期参与非光性母体节律，但这种能力在以后的生活中消失。为了了解在出生后早期的非光夹带背后的机制，时钟基因（Bmal1）表达节律的相位响应外部刺激进行了检查，在培养的SCN收获在出生后第6天。SCN从携带Bmal1表达的生物发光报告基因的转基因小鼠中获得。对于培养基交换，在幼崽和成人中检测到昼夜节律的相位依赖性相移，但幼崽的相移量显着大于成人SCN。在培养的最初几天，一半的幼仔SCN没有表现出综合的昼夜节律。在幼仔中，Bmal 1表达节律的昼夜周期较短，昼夜节律的幅度远低于成年人。它的结论是培养SCN的反应介质交换是在幼鼠比成年小鼠大得多。昼夜节律系统中结构组织的不成熟似乎是幼犬SCN高反应性的基础。
The circadian clock in the suprachiasmatic nucleus of the hypothalamus (SCN) entrains to non-photic maternal rhythms in the fetal and neonatal periods of rodents but this capacity disappears in later life. In order to understand the mechanism behind the non-photic entrainment in the early postnatal period, the phase response of the clock gene (Bmal1) expression rhythm to external stimuli was examined in cultured SCN harvested at postnatal day 6. The SCN was obtained from transgenic mice carrying a bioluminescence reporter for Bmal1 expression. Phase-dependent phase shifts of circadian rhythm were detected in the pup as well as in the adult for culture medium exchange but the amount of phase shift was significantly larger in the pup than in the adult SCN. Half of the pup SCNs did not show integrated circadian rhythmicities in the first few days in culture. In pups, the circadian period of Bmal1 expression rhythm was shorter and the amplitude of circadian rhythm was much lower than in adults. It is concluded that the responsiveness of cultured SCN to medium exchange is much larger in pups than in adult mice. Immaturity of the structural organization in the circadian system seems to underlie the high responsiveness of the pup SCN.