Küry P, Gale N, Connor R, Pasquale E, Guthrie S
Centre for Developmental Neurobiology, Kings' College, London, SE1 9RT, United Kingdom.
Mol Cell Neurosci. 2000 Feb;15(2):123-40. doi: 10.1006/mcne.1999.0812.
Cranial motor axons navigate along a variety of pathways to their targets in the periphery of the head. Whereas somatic motor axons innervate tongue and eye muscles, visceral motor axons innervate parasympathetic ganglia, and branchiomotor axons innervate the branchial arches. The formation of these diverse pathways must depend upon molecules present in the environment traversed by growing axons. We have analyzed the potential roles of the ephrin ligands and their Eph tyrosine kinase receptors during cranial motor neuron development and axon pathfinding, by investigating expression patterns of these molecules at relevant stages in the chick. We detected expression of EphA3 and EphA4 among trigeminal and facial motor neurons, at times when these neurons are projecting to their muscle targets in the branchial arches. Corresponding ephrin-A ligands for these receptors were found to be expressed in specific regions of the arches during the same period, implicating ephrin-mediated interactions in cranial motor axon pathfinding.
颅运动轴突沿着各种路径向头部外周的靶标延伸。躯体运动轴突支配舌肌和眼肌，内脏运动轴突支配副交感神经节，而鳃运动轴突支配鳃弓。这些不同路径的形成必定依赖于生长中的轴突所经过环境中存在的分子。我们通过研究这些分子在鸡发育相关阶段的表达模式，分析了ephrin配体及其Eph酪氨酸激酶受体在颅运动神经元发育和轴突寻路过程中的潜在作用。我们在三叉神经和面运动神经元中检测到EphA3和EphA4的表达，此时这些神经元正朝着鳃弓中的肌肉靶标延伸。在同一时期，发现这些受体相应的ephrin-A配体在鳃弓的特定区域表达，这表明ephrin介导的相互作用在颅运动轴突寻路中发挥作用。
