Smith R S
Department of Surgery, University of Alberta, Edmonton, Canada.
Cell Motil Cytoskeleton. 1988;10(1-2):296-308. doi: 10.1002/cm.970100134.
Rapid organelle transport was studied by computer- and video-enhanced microscopy in the region of localized lesions in single myelinated axons of Xenopus laevis. Localized lesions were created that were either impermeable to small ions in the bathing medium or were permeable to agents with molecular weights up to 10,000. Providing the axons were bathed in a suitable "internal" medium, organelle transport continued to within a few micrometers of the lesion whether the lesion was permeable or not. Organelles undergoing anterograde and retrograde transport reversed their direction of transport on reaching the lesion. In preparations with lesions that were permeable, nonhydrolyzable analogs of ATP inhibited normally directed and reversed organelle transport. In permeable preparations, vanadate and EDTA inhibited retrograde and reversed retrograde transport at different intra-axonal concentrations; anterograde and reversed anterograde transport were also differentially inhibited. Anterograde and retrograde organelle transport were also shown to be inhibited at different intraaxonal concentrations of vanadate and EDTA. The results provide evidence for the existence of two different axonal transport mechanisms in myelinated axons. The two mechanisms can account for the normally directed and reversed transport of individual organelles.
通过计算机和视频增强显微镜技术，对非洲爪蟾单根有髓轴突局部损伤区域的细胞器快速运输进行了研究。制造了局部损伤，这些损伤对浴液中的小离子要么不可渗透，要么对分子量高达10000的物质可渗透。只要轴突浸泡在合适的“内部”介质中，无论损伤是否可渗透，细胞器运输都会持续到损伤部位几微米范围内。进行顺行和逆行运输的细胞器在到达损伤部位时会改变其运输方向。在具有可渗透损伤的制剂中，ATP的非水解类似物抑制正常方向和反向的细胞器运输。在可渗透制剂中，钒酸盐和乙二胺四乙酸（EDTA）在不同的轴突内浓度下抑制逆行和反向逆行运输；顺行和反向顺行运输也受到不同程度的抑制。顺行和逆行细胞器运输在不同的轴突内钒酸盐和EDTA浓度下也被证明受到抑制。这些结果为有髓轴突中存在两种不同的轴突运输机制提供了证据。这两种机制可以解释单个细胞器的正常方向和反向运输。
