Development of corticospinal tract fibers and their plasticity .1. Quantitative analysis of the developing corticospinal tract in mice
Development of corticospinal tract fibers and their plasticity .1. Quantitative analysis of the developing corticospinal tract in mice
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DOI：
10.1016/0387-7604(95)00102-6
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发表时间：
1996-01-01
影响因子：
1.7
通讯作者：
Shimada, M
中科院分区：
文献类型：
--
作者：
Uematsu, J;Ono, K;Shimada, M
本研究旨在从超微结构和定量上研究小鼠颈髓膨大水平皮质脊髓束（CST）轴突的发育。HRP顺行法显示，CST位于背索腹侧1/3处，同侧前索近中端有少量HRP阳性纤维。超微结构上，出生后10天（P10），CST由无髓轴突、生长锥和少量变性轴突组成，以后轴突逐渐增大。在不同日龄计算构成右侧CST的轴突数量。P0、P4、P14、P21和P56的轴突总数分别为2.3 × 10（4）、6.2 × 10（4）、10.4 × 10（4）、7.1 × 10（4）和3.5 × 10（4）。结果表明，小鼠颈膨大期CST轴突数量在P14时达到最大值，随后迅速减少，至P56时达3.5 × 10 ~（4），约68%的轴突丢失。
This study was undertaken to elucidate ultrastructurally and quantitatively the development of the corticospinal tract (CST) axons of mouse at the intumescence level of the cervical cord. An anterograde HRP study showed that the CST was located at the ventral one-third of the dorsal funiculus, and a few HRP-positive fibers were noted at the medialmost part of the ipsilateral anterior funiculus. Ultrastructurally, the CST was composed of unmyelinated axons, growth cones and a few degenerating axons until postnatal day 10 (P10), then the axons in CST gradually increased in size. The number of axons constituting the right CST was calculated at different days of age. The total numbers of axons at P0, P4, P14, P21 and P56 were 2.3 x 10(4), 6.2 x 10(4), 10.4 x 10(4), 7.1 x 10(4) and 3.5 x 10(4), respectively. These results indicate that the number of CST axons at the cervical intumescence of mouse becomes maximum at P14, and then decreases rapidly to reach the adult level of 3.5 x 10(4) (at P56), about 68% of them thus being lost.