Recent work has shown that neuregulin‐4 (NRG4) is a physiological regulator of the growth of sympathetic axons and CNS dendrites in the developing nervous system. Here, we have investigated whether NRG4 plays a role in sensory axon growth and the establishment of cutaneous sensory innervation. Imaging early nerve fibers in the well‐characterized cutaneous trigeminal territory, the brachial plexus, and thorax revealed very marked and highly significant decreases in nerve fiber length and branching density in Nrg4^−/− embryos compared with Nrg4^+/+ littermates. NRG4 promoted neurotrophin‐independent sensory axon growth from correspondingly early trigeminal ganglion and DRG neurons in culture but not from enteroceptive nodose ganglion neurons. High levels of Nrg4 mRNA were detected in cutaneous tissues but not in sensory ganglia. Our findings suggest that NRG4 is an important target‐derived factor that participates in the establishment of early cutaneous sensory innervation.

中文翻译：

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Neuregulin-4 有助于建立皮肤感觉神经支配

最近的研究表明，neuregulin-4 (NRG4) 是发育中神经系统中交感神经轴突和 CNS 树突生长的生理调节剂。在这里，我们研究了 NRG4 是否在感觉轴突生长和皮肤感觉神经支配的建立中起作用。与Nrg4 ^+/+同窝小鼠相比，对特征明确的皮肤三叉神经区域、臂丛和胸部的早期神经纤维进行成像显示，Nrg4 ^-/-胚胎的神经纤维长度和分支密度非常显着且非常显着降低。NRG4 促进了培养中相应的早期三叉神经节和 DRG 神经元的神经营养因子非依赖性感觉轴突生长，但不促进肠感受性结节神经元的生长。高水平在皮肤组织中检测到Nrg4 mRNA，但在感觉神经节中未检测到。我们的研究结果表明，NRG4 是一个重要的靶衍生因子，参与了早期皮肤感觉神经支配的建立。