Liang Xitong, Holy Timothy E, Taghert Paul H
Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA.
Science. 2016 Feb 26;351(6276):976-81. doi: 10.1126/science.aad3997.
In Drosophila, molecular clocks control circadian rhythmic behavior through a network of ~150 pacemaker neurons. To explain how the network's neuronal properties encode time, we performed brainwide calcium imaging of groups of pacemaker neurons in vivo for 24 hours. Pacemakers exhibited daily rhythmic changes in intracellular Ca(2+) that were entrained by environmental cues and timed by molecular clocks. However, these rhythms were not synchronous, as each group exhibited its own phase of activation. Ca(2+) rhythms displayed by pacemaker groups that were associated with the morning or evening locomotor activities occurred ~4 hours before their respective behaviors. Loss of the receptor for the neuropeptide PDF promoted synchrony of Ca(2+) waves. Thus, neuropeptide modulation is required to sequentially time outputs from a network of synchronous molecular pacemakers.
在果蝇中，分子时钟通过一个由约150个起搏器神经元组成的网络来控制昼夜节律行为。为了解释该网络的神经元特性如何编码时间，我们在体内对起搏器神经元群体进行了24小时的全脑钙成像。起搏器表现出细胞内Ca(2+)的每日节律性变化，这些变化受环境线索的调节并由分子时钟定时。然而，这些节律并不同步，因为每个群体都表现出自己的激活阶段。与早晨或傍晚运动活动相关的起搏器群体所显示的Ca(2+)节律在其各自行为发生前约4小时出现。神经肽PDF受体的缺失促进了Ca(2+)波的同步。因此，需要神经肽调节来依次定时来自同步分子起搏器网络的输出。
