CLUSTER OF VOLTAGE SENSITIVE NA CHANNELS ON AXONS IS INDEPENDENT OF SCHWANN CELL

大鼠轴突上电压敏感性钠通道的分布 营养不良小鼠的背根和腹根 用免疫细胞化学方法检测129/Rej-Lama2dy。在这些 神经中有雪旺细胞无法增殖的区域 和正常方式的髓鞘轴突，留下紧密的 充填的大直径淀粉样轴突。我们已经确认了离散的 以及钠通道免疫反应性的焦点浓度 轴突共聚焦免疫荧光、免疫电子显微镜和 中电压电子显微镜(IVEM) 多肽源性多克隆抗体。此外，同步 神经元特异性骨架蛋白G识别抗体的标记 发现两者的钠通道有明显的共定位 正常轴突和淀粉样轴突。钠斑块的存在 通道及其在淀粉化轴突上的锚定蛋白 雪旺细胞的缺失表明轴突可以 独立形成和维护这些初始聚合。这 确认雪旺细胞和轴突之间的直接接触不是 形成结节钠通道斑块所必需的 尺寸和密度。此外，这强烈地表明， 钠通道从雪旺细胞到轴突的局部转移不是 此过程所需的。这项研究发表在 神经科学(Deerinck等人，《神经科学杂志》，17：5080-5088,1997)。

The distribution of voltage sensitive sodium channels on axons in the dorsal and ventral spinal roots of the dystrophic mouse 129/ReJ-Lama2dy was determined using immunocytochemistry. In these nerves there are regions in which Schwann cells fail to proliferate and myelinate axons in a normal fashion, leaving bundles of closely packed large diameter amyelinated axons. We have identified discrete and focal concentrations of sodium channel immunoreactivity on these axons by confocal immunofluorescence, immunoelectron microscopy and Intermediate Voltage Electron Microscopy (IVEM) using a peptide-derived polyclonal antibody. In addition, simultaneous labeling with an antibody recognizing neuronal-specific ankyrinG revealed a distinct colocalization with the sodium channels on both normal and amyelinated axons. The presence of patches of sodium channels along with their anchoring protein on amyelinated axons in the absence of intervening Schwann cells demonstrates that axons can independently form and maintain these initial aggregations. This confirms that direct contact between Schwann cell and axon is not required for the formation of sodium channel patches of nodal dimensions and density. Furthermore, this strongly suggests that local transfer of sodium channels from Schwann cells to axons is not required for this process. This work was published in the Journal of Neuroscience (Deerinck et al., J. Neurosci., 17: 5080-5088, 1997).