Axonal regeneration of descending and ascending spinal projection neurons in spinal cord-transected larval lamprey
Axonal regeneration of descending and ascending spinal projection neurons in spinal cord-transected larval lamprey
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DOI：
10.1016/s0014-4886(02)00057-2
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发表时间：
2003-04-01
影响因子：
5.3
通讯作者：
McClellan, AD
中科院分区：
文献类型：
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作者：
Armstrong, J;Zhang, L;McClellan, AD
下行和上行脊髓投射神经元的分布（即，具有中等至长轴突的脊髓神经元）在正常的幼体七鳃鳗和在50%体长（BL，距前头部的标准化距离）处完全脊髓横断后恢复8周的动物中进行比较。在正常动物中，HRP应用于60%BL（40%BL）的脊髓，沿着头（尾）侧脊髓平均标记713.8 ± 143.2个脊髓下行投射神经元（718.4 ± 108.0个脊髓上行投射神经元），其中大多数是未鉴定的神经元。这些神经元中的一些投射至少类似于50 -60个脊髓节段（在本研究中使用的平均长度类似于90 mm的动物中类似于36 -47 mm）。切断后8周，HRP标记的下行或上行脊髓神经元的数量，延长其轴突通过切断约40%的正常动物的脊髓类似地区。因此，在幼体七鳃鳗中，下行和上行脊髓投射神经元的轴突再生是不完全的，类似于下行脑神经元的轴突再生（Davis和McClellan，1994 a）。大多数恢复的预测是从身份不明的脊髓神经元，以前没有记录。与其他几种低等脊椎动物的结果相反，七鳃鳗的脊髓神经元呈现出明显的轴突再生。已鉴定的下行脊髓神经元，如外侧中间神经元和交叉的对侧中间神经元，以及已鉴定的上行脊髓神经元，如巨型中间神经元和边缘细胞，在动物中再生出的轴突至少超过横断部位9 mm，平均长度接近90 mm，这比以前报道的明显更远。相比之下，大多数背侧细胞，这是位于中央的感觉神经元，表现出非常少的轴突再生。(C)2003 Elsevier Science（美国）。All rights reserved.
The distributions of descending and ascending spinal projection neurons (i.e., spinal neurons with moderate to long axons) were compared in normal larval lamprey and in animals that had recovered for 8 weeks following a complete spinal cord transection at 50% body length (BL, normalized distance from the anterior head). In normal animals, application of HRP to the spinal cord at 60% BL (40% BL) labeled an average of 713.8 +/- 143.2 descending spinal projection neurons (718.4 +/- 108.0 ascending spinal projection neurons) along the rostral (caudal) spinal cord, most of which were unidentified neurons. Some of these neurons project for at least similar to50-60 spinal cord segments (similar to36-47 mm in animals with an average length of similar to90 mm used in the present study). At 8 weeks posttransection, the numbers of HRP-labeled descending or ascending spinal neurons that extended their axons through the transection were about 40% of those in similar areas of the spinal cord in normal animals. Thus, in larval lamprey, axonal regeneration of descending and ascending spinal projection neurons is incomplete, similar to that found for descending brain neurons (Davis and McClellan, 1994a). The majority of restored projections were from unidentified spinal neurons that have not been documented previously. In contrast to results from several other lower vertebrates, in the lamprey ascending spinal neurons exhibited substantial axonal regeneration. Identified descending spinal neurons, such as lateral intemeutons and crossed contralateral interneurons, and identified ascending spinal neurons, such as giant interneurons and edge cells, regenerated their axons at least 9 mm beyond the transection site in animals with an average length of similar to90 mm, which is appreciably farther than previously reported. In contrast, most dorsal cells, which are centrally located sensory neurons, exhibited very little axonal regeneration. (C) 2003 Elsevier Science (USA). All rights reserved.