Control of axonal caliber by neurofilament transport.
Control of axonal caliber by neurofilament transport.
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DOI：
10.1083/jcb.99.2.705
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发表时间：
1984-08
期刊：
影响因子：
--
通讯作者：
Price DL
中科院分区：
文献类型：
--
作者：
Hoffman PN;Griffin JW;Price DL
神经丝（神经细胞的中间纤维）的作用是理论性的。以前的形态学研究表明，神经丝含量和轴突口径之间的密切关系。在这项研究中，再生的神经元被用来作为一个模型系统，用于测试的假设，即神经丝是轴突口径的内在决定因素，神经丝的含量是由轴突运输的神经丝控制。选择该系统是因为先前的研究已经表明，轴突切断后，轴突口径在再生神经的近端残端内减小，并且因为在再生轴突中经历轴突运输的神经丝蛋白的相对量选择性地减少。轴突口径和神经丝数量之间的关系进行了检查，在一个系统的方式在再生和控制运动轴突在大鼠L5腹根。重建的空间和时间序列的轴突萎缩的近端残端轴突切断术后显示，轴突口径的减少首先检测到在最近端区域的根，随后在近端到远端方向进展的速度为1.7毫米/天，这是相同的神经丝运输在这些神经元的速率。定量超微结构研究表明，这些口径的减少与轴突神经丝数量的成比例减少有关，但与微管无关。这些结果支持神经丝含量是轴突口径的主要内在决定因素和神经丝含量由神经丝的轴突运输控制的假设。在此基础上，我们建议的轴突体积的控制神经丝的作用。
The role of neurofilaments, the intermediate filaments of nerve cells, has been conjectural. Previous morphological studies have suggested a close relationship between neurofilament content and axonal caliber. In this study, the regenerating neuron was used as a model system for testing the hypotheses that neurofilaments are intrinsic determinants of axonal caliber, and that neurofilament content is controlled by the axonal transport of neurofilaments. This system was chosen because previous studies had shown that, after axotomy, axonal caliber was reduced within the proximal stump of the regenerating nerve and, because the relative amount of neurofilament protein undergoing axonal transport in regenerating axons was selectively reduced. The relationship between axonal caliber and neurofilament number was examined in a systematic fashion in both regenerating and control motor axons in rat L5 ventral root. Reconstruction of the spatial and temporal sequences of axonal atrophy in the proximal stump after axotomy showed that reductions in axonal caliber were first detected in the most proximal region of the root and subsequently progressed in a proximal-to-distal direction at a rate of 1.7 mm/day, which is identical to the rate of neurofilament transport in these neurons. Quantitative ultrastructural studies showed that these reductions in caliber correlated with a proportional decrease in the number of axonal neurofilaments but not microtubules. These results support the hypotheses that neurofilament content is a major intrinsic determinant of axonal caliber and that neurofilament content is controlled by the axonal transport of neurofilaments. On this basis, we suggest a role for neurofilaments in the control of axonal volume.