Department of Physiology and Biophysics, University of Colorado at the Anschutz Medical Center, Aurora, Colorado, USA.
Ann N Y Acad Sci. 2010 Jun;1198:201-7. doi: 10.1111/j.1749-6632.2009.05426.x.
At early embryonic stages, zebrafish spinal neuron subtypes can be distinguished and accessed for physiological studies. This provides the opportunity to determine electrophysiological properties of different spinal motor neuron subtypes. Such differences have the potential to then regulate, in a subtype-specific manner, activity-dependent developmental events such as axonal outgrowth and pathfinding. The zebrafish spinal cord contains a population of early born neurons. Our recent work has revealed that primary motor neuron (PMN) subtypes in the zebrafish spinal cord differ with respect to electrical properties during early important periods when PMNs extend axons to their specific targets. Here, we review recent findings regarding the development of electrical properties in PMN subtypes. Moreover, we consider the possibility that electrical activity in PMNs may play a cell nonautonomous role and thus influence the development of later developing motor neurons. Further, we discuss findings that support a role for a specific sodium channel isoform, Nav1.6, expressed by specific subtypes of spinal neurons in activity-dependent processes that impact axonal outgrowth and pathfinding.
在早期胚胎阶段，可以区分斑马鱼脊髓神经元亚型，并用于生理研究。这为确定不同脊髓运动神经元亚型的电生理特性提供了机会。这种差异有可能以特定于亚型的方式调节活动依赖性发育事件，如轴突生长和轨迹形成。斑马鱼脊髓包含一群早期出生的神经元。我们最近的工作表明，斑马鱼脊髓中的原代运动神经元（PMN）亚型在 PMN 延伸轴突到其特定靶标时的早期重要时期，在电特性方面存在差异。在这里，我们回顾了关于 PMN 亚型电特性发育的最新发现。此外，我们还考虑了 PMN 中的电活动可能发挥非自主细胞作用的可能性，并因此影响后期发育的运动神经元的发育。此外，我们还讨论了支持特定钠离子通道亚型 Nav1.6 在影响轴突生长和轨迹形成的活动依赖性过程中发挥作用的发现，该亚型由脊髓神经元的特定亚型表达。
