French A S, Sanders E J, Duszyk E, Prasad S, Torkkeli P H, Haskins J, Murphy R A
Department of Physiology, University of Alberta, Edmonton, Canada.
J Neurobiol. 1993 Jul;24(7):939-48. doi: 10.1002/neu.480240707.
Antibodies to channel proteins and specific peptide sequences have been previously used to localize voltage-activated sodium channels in the rat brain. Here we describe the first localization of sodium channels in an insect nervous system using a site-directed antibody. The mesothoracic ganglion of the cockroach was stained with an antibody to the highly conserved SP19 sequence. Antibody labelling was visualized by light microscopy using the avidin/biotin method on wax sections, and transmission electron microscopy of immunogold-labelled thin sections. Central ganglia of insects contain clearly separated regions of cell bodies, synaptic neuropil, axon tracts, and nerves. Antibody staining by light microscopy was limited to neurons, and was intense in axons throughout the ganglion and nerves. Staining was also strong in the cytoplasm, but not the nuclei, of many neuronal cell bodies. Neuropil regions were relatively lightly labelled. These findings can be correlated with the known electrophysiology of the ganglion. Electron microscopy detected sodium channels in areas surrounding axons, probably including axon membranes and enveloping glial cell membranes. Axonal mitochondria were also heavily labelled, suggesting a sodium channel transport function for these organelles.
此前，通道蛋白抗体和特定肽序列已被用于在大鼠脑中定位电压激活钠通道。在此，我们描述了使用位点特异性抗体首次在昆虫神经系统中定位钠通道。用针对高度保守的SP19序列的抗体对蟑螂的中胸神经节进行染色。使用抗生物素蛋白/生物素方法在蜡切片上通过光学显微镜以及免疫金标记薄切片的透射电子显微镜观察抗体标记情况。昆虫的中枢神经节包含细胞体、突触神经纤维网、轴突束和神经等明显分开的区域。光学显微镜下的抗体染色仅限于神经元，并且在整个神经节和神经的轴突中染色强烈。许多神经元细胞体的细胞质中染色也很强，但细胞核中没有。神经纤维网区域标记相对较轻。这些发现可以与神经节已知的电生理学相关联。电子显微镜在轴突周围区域检测到钠通道，可能包括轴突膜和包绕的神经胶质细胞膜。轴突线粒体也被大量标记，表明这些细胞器具有钠通道转运功能。
