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Scientists long believed that two nerve clusters in the human hypothalamus, called suprachiasmatic nuclei (SCNs), were what controlled our circadian rhythms. Those rhythms are the biological cycles that recur approximately every 24 hours in synchronization with the cycle of sunlight and darkness caused by Earth’s rotation. Studies have demonstrated that in some animals, the SCNs control daily fluctuations in blood pressure, body temperature, activity level, and alertness, as well as the nighttime release of the sleep-promoting agent melatonin. Furthermore, cells in the human retina dedicated to transmitting information about light levels to the SCNs have recently been discovered. Four critical genes governing circadian cycles have been found to be active in every tissue, however, not just the SCNs, of flies, mice, and humans. In addition, when laboratory rats that usually ate at will were fed only once a day, peak activity of a clock gene in their livers shifted by 12 hours, whereas the same clock gene in the SCNs remained synchronized with light cycles. While scientists do not dispute the role of the SCNs in controlling core functions such as the regulation of body temperature and blood pressure, scientists now believe that circadian clocks in other organs and tissues may respond to external cues other than light—including temperature changes—that recur regularly every 24 hours.
以上是原文
长期以来，人们认为下丘脑中的两个神经簇——被称为视交叉上核（SCNs），控制了我们的昼夜规律。这些节奏是生物周期，大约每24小时重复一次，与地球自转引起的阳光和黑暗循环同步。研究表明，在一些动物中，SCNs 控制着血压、体温、活动水平和警觉性的日常波动，以及促睡眠的褪黑激素的夜间释放。此外，人类视网膜细胞致力于将有关光的信息传递给 scn 的细胞最近被发现。
四个控制生理周期的关键基因被发现活跃在每一个组织，然而，不仅仅是苍蝇，老鼠和人类的SCNs中。此外，实验室老鼠通常在意志状态下吃东西，每天只喂食一次，它们肝脏中的钟基因活性峰值每12小时发生变化，而同样的时钟基因在 SCNs 中与光周期保持同步。虽然科学家们并不否认 SCNs 在控制体温和血压调节等核心功能方面的作用，但科学家现在认为，其他器官和组织中的生物钟可能对光以外的外部线索有反应——包括温度的变化——每隔24小时定期重复。 以上是译文
请问大家这篇文章的意思是说， 光的信息传递给SCN→SCN控制血压、体温、活动水平和警觉性的日常波动，以及促睡眠的褪黑激素的夜间释放。但是最近发现一些器官的活性变化是12小时，与scn中的24小时不一样，因此，虽然不否认scn的重要作用，但是其他器官的活性变化跟光无关。 请问大家上面的两行考虑是对的吗》 文章要表达的是 scn有重要作用（且与光有关），但是其他器官也会对光以外的其他因素产生反应？？ 是这样吗？？谢谢大家
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发表于 2018-9-3 10:42:09
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