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【bio-news】随季节而变的昼夜节律生物钟
随季节而变的昼夜节律生物钟
Michael Rosbash
New research has revealed what keeps animals' internal clocks running on time through the long nights of winter, the long days of summer, and everything in between. The research, reported in the April 6, 2007, issue of Cell, shows that a specific network of brain cells is the key to synchronizing the circadian clock to environmental cues, and reveals an astonishing degree of flexibility within the system.
无论是经过冬季的漫漫长夜，还是夏天的长白昼，抑或在这两个季节中间任何时间，新研究揭示了动物体内生物钟是如何保持其准时工作的机制。发表在2007年4月6日《细胞》杂志上的研究显示大脑细胞的一种特殊网络系统是使昼夜节律生物钟和环境因素协调一致的关键所在，并揭示了在该系统内的惊人程度的适应性。
Howard Hughes Medical Institute investigator Michael Rosbash, who led the study, says the findings—gleaned from work on the fruit fly Drosophila—have broad implications for understanding how innate behaviors such as mating, migrating, and hibernating are stimulated by environmental cues. Dan Stoleru, the lead author of the Cell paper and a postdoctoral fellow in Rosbash's laboratory at Brandeis University, adds that the study reveals insights into possible causes of seasonal depression as well as other forms of mood disorders that respond to light therapy.
该研究的负责人霍华德-休斯医学研究所研究员Michael Rosbash称，该发现－收集自黑腹果蝇上的研究－对理解诸如交配、迁徙和冬眠等固有行为是如何受环境因素刺激的有着广泛影响。这篇《细胞》杂志文献的第一作者、布兰德斯大学Rosbash实验室的博士后Dan Stoleru补充说，本研究为找到对各种光治疗后情感性障碍和季节性抑郁的可能病因提供了崭新的视角。
“The major implication of this paper is that it is the brain network that gives the circadian clock such great plasticity. This allows an animal to adapt to environmental change, which includes seasonality, but may include other less predictable events. We anticipate that a similar phenomenon takes place in mammals, including humans,” said Rosbash.
Rosbash说：“本文的主要含义在于突出给予昼夜节律生物钟如此巨大可塑性的是大脑网状系统。其可允许动物适应的环境变迁，包括季节性，但也许还包括其它较少预料事件。我们期望类似的现象会在包括人在内的哺乳动物上发生。”
Circadian clocks in living creatures usually operate on a time cycle that varies between 22 and 26 hours in artificially constant environments. Connections with the light-dark cycle of the external world make the cycle 24 hours. The human circadian clock tells us when to sleep and awaken and controls important physiologies involving hormones, body temperature, heart function, and oxygen consumption. In the fruit fly, the circadian function appears important for regulating periods of activity, analogous to the human sleep-wake cycle. Fruit flies have two characteristic peaks of activity, one in the morning and the other in the early evening, and each is controlled genetically by a separate group of brain circadian cells.
在人工恒定环境下，活体生物的昼夜节律生物钟通常运行的时间周期在22到26小时不等。处在外部世界的昼夜循环时将调节该循环周期成24小时。人类昼夜节律生物钟告诉人们什么时间睡觉和清醒，并控制重要的生理机能，例如激素分泌、体温保持、心脏功能和氧耗量。在果蝇上，昼夜节律机能表现出对调节活动时间的重要性，可模拟出人类睡眠－觉醒周期。果蝇有双活动性特征峰，一个在早晨，另一个在傍晚，每一个都是在独立的脑昼夜节律细胞遗传控制下。
Rosbash is a leader in the field of circadian research. For the past 25 years he has been defining the machinery that underlies the nearly universal pattern of circadian rhythms in insects, animals, and humans. He employs the tools of Drosophila genetics to understand how the circadian clock ticks and which master neural circuits underlie circadian activity patterns.
Rosbash是昼夜节律研究领域的顶级专家。25年来，他一直致力于确定构成昼夜循环节奏近乎普遍模式的基础，包括在昆虫、动物和人上。他运用果蝇遗传学作为工具理解昼夜节律生物钟如何运行和哪一个神经环路构成昼夜节律活动模式的基础。
For the past several years, Rosbash's team has focused on these two groups of neurons known as “morning cells” and “evening cells.” Studies led by Stoleru showed that these two cell groups constitute the master network and represent a dual control system over the circadian clock. In the current study, Stoleru altered the expression of genes in the separate centers of this circuit and observed the flies' activity patterns under conditions of total light, total darkness, and different combinations of periods of light and dark. Notably, he found that a gene called shaggy, whose human equivalent GSK-3 is a target of lithium therapy for severe affective disorders, is critical to conveying the information on light change to the clock machinery.
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作者:admin@医学,生命科学 2011-04-16 17:11
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