Entraining signals initiate behavioral circadian rhythmicity in larval zebrafish
Entraining signals initiate behavioral circadian rhythmicity in larval zebrafish
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DOI：
10.1177/074873002129002618
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发表时间：
2002-08-01
影响因子：
3.5
通讯作者：
Cahill, GM
中科院分区：
文献类型：
--
作者：
Hurd, MW;Cahill, GM
作者表明，调节斑马鱼幼体运动活动的生物钟在生命的前4天逐渐发展，并且在胚胎发育后期暴露于夹带信号对于启动稳健的行为节律性是必要的。当斑马鱼幼虫从光暗（LD）周期转移到恒定黑暗（DD）的第三或第四天受精后，几乎所有的鱼的运动活动是有节奏的第5至第9天受精后，与峰值活动发生在主观的一天。四个LD周期后的节律幅度高于三个LD周期后的节律幅度。当胚胎在受精后第二天从LD转移到DD时，只有大约一半的动物后来表现出统计学上显著的活动节律。这些节律噪音较大，振幅较低，但相位正常。当斑马鱼提出DD开始在受精后14小时，只有22%的人表示显着的昼夜节律作为幼虫。这些节律是低振幅和相位锁定的时间处理的第三天，而不是母亲的LD周期。这些结果表明，斑马鱼的行为节律是由一个起搏系统调节的，该系统在胚胎发育的第二天对光敏感，但继续发育到第四天。这种起搏系统需要环境信号来启动或同步昼夜节律。
The authors show that a circadian clock that regulates locomotor activity in larval zebrafish develops gradually over the first 4 days of life and that exposure to entraining signals late in embryonic development is necessary for initiation of robust behavioral rhythmicity. When zebrafish larvae were transferred from a light-dark (LD) cycle to constant darkness (DD) on the third or fourth day postfertilization, the locomotor activity of almost all fish was rhythmic on days 5 to 9 postfertilization, with peak activity occurring during the subjective day. Rhythm amplitude was higher after four LD cycles than after three LD cycles. When embryos were transferred from LD to DD on the second day postfertilization, only about half of the animals later displayed statistically significant activity rhythms. These rhythms were noisier and of lower amplitude, but phased normally. When zebrafish were raised in DD beginning at 14 h postfertilization, only 22% of them expressed significant circadian rhythmicity as larvae. These rhythms were of low amplitude and phase-locked to the time of handling on the third day rather than to the maternal LD cycle. These results show that behavioral rhythmicity in zebrafish is regulated by a pacemaking system that is sensitive to light by the second day of embryogenesis but continues to develop into the fourth day. This pacemaking system requires environmental signals to initiate or synchronize circadian rhythmicity.