Goodrum J F, Toews A D, Morell P
Brain Res. 1979 Nov 2;176(2):255-72. doi: 10.1016/0006-8993(79)90982-x.
The axonal transport of labeled macromolecules in retinal ganglion cells of rats was investigated from 1 to 20 days following intraocular injection of [3H]fucose and [35S]sulfate. Maximal incorporation of [3H]fucose into acid insoluble material in the retina was at 8 h, followed by a biphasic decline. Transported [3H]fucose (98% as glycoprotein) was in the optic nerve at 1 h, the optic tract and lateral geniculate body by 2 h, and the superior colliculus by 3 h after injection, indicating a rate of transport of approximately 200 mm/day. Radioactivity continued to accumulate in the superior colliculus for at least 8 h and began to decline rapidly by 24 h. Between 3 and 6 days levels rose again in both optic tract and superior colliculus before starting a gradual decline, indicating that a wave of rapidly transported material was delayed in leaving the retina. When proteins in the superior colliculus were fractionated by gel electrophoresis, the composition of the two fucosylated protein transport phases could be partially resolved. Radioactivity in individual gel peaks represented primarily in the first phase decayed with an average half-life of one day, althouth that in one prominent protein of molecular weight 280,000 turned over with a half-life of the order of 12 h. Radioactive peaks primarily in the second phase decayed with an average half-life of more than a week. Incorporation of [35S]sulfate into acid insoluble material in the retina was maximal at 1-2 h, after which there was a rapid loss of label. The appearance of [35S]sulfate in the optic tract, lateral geniculate body and superior colliculus preceded by a short time that of the [3H]fucose; indicating a shorter retinal processing time for this label. The total transported [35S]sulfate in the superior colliculus peaked by 4-8 h and had fallen by 65% at one day; no prominent second wave of transport was observed as was the case for [3H]fucose. Acid insoluble [35S]sulfate in the superior colliculus was equally divided between glycopeptides and glycosaminoglycans at all times examined, indicating that these macromolecules are transported at the same rate. [35S]Sulfate incorporated into various proteins fractionated by gel electrophoresis had heterogeneous turnover rates, the average being around 12 h. Radioactivity in one group of proteins, of molecular weight around 90,000, decayed with a half-life of only a few hours.
在大鼠眼内注射[3H]岩藻糖和[35S]硫酸盐后1至20天，研究了标记大分子在大鼠视网膜神经节细胞中的轴突运输。[3H]岩藻糖在视网膜中最大程度地掺入酸不溶性物质的时间是在8小时，随后呈双相下降。注射后1小时，运输的[3H]岩藻糖（98%为糖蛋白）出现在视神经中，2小时后出现在视束和外侧膝状体，3小时后出现在上丘，表明运输速度约为200毫米/天。放射性在上丘中持续积累至少8小时，并在24小时时开始迅速下降。在3至6天之间，视束和上丘中的水平再次上升，然后开始逐渐下降，这表明一波快速运输的物质在离开视网膜时被延迟。当上丘中的蛋白质通过凝胶电泳进行分级分离时，两个岩藻糖化蛋白质运输阶段的组成可以部分分辨出来。单个凝胶峰中的放射性在第一阶段主要以平均半衰期一天衰减，尽管分子量为280,000的一种突出蛋白质的半衰期约为12小时。主要在第二阶段的放射性峰以平均半衰期超过一周的速度衰减。[35S]硫酸盐在视网膜中最大程度地掺入酸不溶性物质的时间是在1至2小时，之后标记迅速丢失。[35S]硫酸盐在视束、外侧膝状体和上丘中的出现时间比[3H]岩藻糖略早；这表明这种标记的视网膜处理时间较短。上丘中运输的[35S]硫酸盐总量在4至8小时达到峰值，一天时下降了65%；未观察到像[3H]岩藻糖那样明显的第二波运输。在上丘中，酸不溶性[35S]硫酸盐在所有检测时间点在糖肽和糖胺聚糖之间平均分配，这表明这些大分子以相同的速度运输。通过凝胶电泳分级分离的各种蛋白质中掺入的[35S]硫酸盐具有不同的周转速率，平均约为12小时。一组分子量约为90,000的蛋白质中的放射性以仅几小时的半衰期衰减。
