Synaptic silencing of fast muscle is compensated by rewired innervation of slow muscle
Synaptic silencing of fast muscle is compensated by rewired innervation of slow muscle
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DOI：
10.1126/sciadv.aax8382
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发表时间：
2020-04-01
期刊：
影响因子：
13.6
通讯作者：
Ono, Fumihito
中科院分区：
文献类型：
--
作者：
Zempo, Buntaro;Yamamoto, Yasuhiro;Ono, Fumihito
几十年来，许多研究表明，快速肌肉有助于快速运动，而慢速肌肉则是需要耐力的运动的基础。通过产生突变的斑马鱼的快速肌肉突触沉默，我们研究了快速肌肉的贡献，在幼体和成年斑马鱼。在幼虫阶段，突变体缺乏对触觉刺激的特征性惊吓反应：躯干弯曲（C-弯曲），然后是强劲的向前推进。出乎意料的是，成年突变体沉默快速肌肉表现出强大的C弯曲和向前推进刺激后。逆行标记显示，运动神经元在基因上被编程为在快肌肉上形成突触，而不是改变路线并支配慢肌肉，这导致慢肌肉和中间肌肉部分转化为快肌肉。因此，快速肌肉突触的延长沉默改变了运动神经元的神经支配，并引起肌肉细胞类型的转换，揭示了一个意想不到的运动适应机制。
For decades, numerous studies have proposed that fast muscles contribute to quick movement, while slow muscles underlie locomotion requiring endurance. By generating mutant zebrafish whose fast muscles are synaptically silenced, we examined the contribution of fast muscles in both larval and adult zebrafish. In the larval stage, mutants lacked the characteristic startle response to tactile stimuli: bending of the trunk (C-bend) followed by robust forward propulsion. Unexpectedly, adult mutants with silenced fast muscles showed robust C-bends and forward propulsion upon stimulation. Retrograde labeling revealed that motor neurons genetically programmed to form synapses on fast muscles are instead rerouted and innervate slow muscles, which led to partial conversion of slow and intermediate muscles to fast muscles. Thus, extended silencing of fast muscle synapses changed motor neuron innervation and caused muscle cell type conversion, revealing an unexpected mechanism of locomotory adaptation.