ALTERED RATIO BETWEEN AXON DIAMETER AND MYELIN SHEATH THICKNESS IN REGENERATED NERVE FIBERS
ALTERED RATIO BETWEEN AXON DIAMETER AND MYELIN SHEATH THICKNESS IN REGENERATED NERVE FIBERS
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DOI：
10.1016/0006-8993(72)90215-6
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发表时间：
1972-01-01
期刊：
影响因子：
2.9
通讯作者：
SCHRODER, JM
中科院分区：
文献类型：
--
作者：
SCHRODER, JM
损伤后6-24个月的再生神经纤维的精细结构在几个方面与正常神经纤维不同：(1)最粗的再生神经纤维比最厚的正常神经纤维薄。(2)尽管一些轴突变得相当大，但最厚的再生纤维的髓鞘仍然相对较薄。(3)有髓纤维和无髓纤维的相当大的重叠被发现是由于一定比例的嗜主动脉、有髓轴突和许多无髓鞘、粗轴突的直径相等。因此，再生神经纤维轴突直径与髓鞘厚度之间的回归曲线比正常神经的轴突直径与髓鞘厚度呈斜率递增。本实验观察了犬神经移植物远端再生的神经纤维，以及在较有利的再生条件下，大鼠损伤远端的再生神经纤维。在大鼠中，最厚的再生轴突及其髓鞘最终达到了相对和绝对比狗更大的尺寸。这表明观察到的最厚的再生神经纤维的髓鞘厚度的减少是已知的再生神经纤维传导速度下降的主要原因。
The fine structure of regenerated nerve fibers, 6–24 months after a lesion, differed from that of normal nerve fibers in several respects:(1) The thickest regenerated nerve fibers were thinner than the thickest normal ones.(2) Although some axons became rather large, the myelin sheats of the thickest regenerated fibers remained relatively thin.(3) A considerable overlap of myelinated and unmyelinated fibers was found to be due to equal diameters of a proportion of aorophic, myelinated axons with extraordinarily thick sheaths, and of a number of unmyelinated, thick axons.Accordingly, the regression line for the relation between the axon diameter and the myelin sheath thickness of regenerated nerve fibers increased more gradually in slope than did that for normal nerves.These observations were made on regenerated nerve fibers both distal to nerve grafts in dogs and, under more favorable conditions for regeneration, distal to crush lesions in rats. The thickest regenerated axons, and their myelin sheaths, finally reached greater dimensions, relatively and absolutely, in rats than in dogs.It is suggested that the observed reduction of the myelin sheath thickness of the thickest regenerated nerve fibers constitutes tha main cause for the known decrease of the conduction velocity of regenerated nerve fibers.