Masuda Tomoyuki, Shiga Takashi
Department of Anatomy, Fukushima Medical University, School of Medicine, Fukushima 960-1295, Japan.
Neurosci Res. 2005 Apr;51(4):337-47. doi: 10.1016/j.neures.2005.01.007.
Research in the past decade has advanced our knowledge of the key role that diffusible cues play in axonal guidance during development. In higher vertebrates, dorsal root ganglion (DRG) neurons extend axons centrally to the spinal cord through the dorsal root entry zone and peripherally to muscle and skin targets. In this review, we focus on the role of proximate "non-target" tissues in the initial stages of DRG axonal growth. In the early stages of development, "non-target" tissues including the dermamyotome, the notochord, and the ventral spinal cord exert chemorepulsion for DRG axons. We describe how semaphorin 3A, chondroitin sulfate proteogrycans, and cell adhesion molecules participate in chemorepulsion and the way they provide spatio-temporal specificity to chemorepulsion. Axon chemorepulsion may act not only to shape DRG axonal trajectories but it also affects a variety of other axonal projections in the peripheral and central nervous system.
过去十年的研究增进了我们对可扩散信号在发育过程中轴突导向方面关键作用的认识。在高等脊椎动物中，背根神经节（DRG）神经元的轴突通过背根进入区向脊髓中央延伸，并向肌肉和皮肤靶点周围延伸。在本综述中，我们重点关注临近的“非靶标”组织在DRG轴突生长初始阶段所起的作用。在发育早期，包括皮肌节、脊索和脊髓腹侧在内的“非靶标”组织对DRG轴突施加化学排斥作用。我们描述了信号素3A、硫酸软骨素蛋白聚糖和细胞黏附分子如何参与化学排斥作用，以及它们为化学排斥作用提供时空特异性的方式。轴突化学排斥作用不仅可能影响DRG轴突的轨迹形成，还会影响周围和中枢神经系统中的各种其他轴突投射。
