Mitochondrial accumulation in the distal part of the initial segment of chicken spinal motoneurons
Mitochondrial accumulation in the distal part of the initial segment of chicken spinal motoneurons
复制标题
DOI：
10.1016/j.brainres.2004.08.016
复制
发表时间：
2004-11-12
期刊：
影响因子：
2.9
通讯作者：
Atsumi, S
中科院分区：
文献类型：
--
作者：
Li, YC;Zhai, XY;Atsumi, S
轴突起始段是动作电位的起始位点，其形态学特征为致密的底涂层和通过跨桥连接的微管束。为了分析初始节段的亚细胞结构，我们通过将辣根过氧化物酶（HRP）注射到肌肉中逆行运输，对已识别的鸡运动神经元的初始节段进行了连续横切。初始段的平均 (+/-SD) 长度为 28.1 +/- 2.3 mm (n=6)。线粒体聚集在初始节段的远端，长度为1.4-6.9μm（占初始节段总长度的5-23%）。在远端部分的横切面中，线粒体密度为15.8+/-6.2%(n=5)，而在中部和近端部分中，线粒体密度分别为6.1+/-1.6%和5.6+/-1.4%。线粒体积聚在鸡的阶段性和强直性运动神经元中常见，并且在未注射HRP的鸡的大腹角神经元起始段的远端部分也观察到线粒体积聚。这些发现表明积累的线粒体在维持运动神经元初始节段远端的生理功能中发挥重要作用。 (C) 2004 Elsevier B.V. 保留所有权利。
The axonal initial segment is the initiation site of action potentials and is characterized morphologically by a dense undercoating and fascicles of microtubules connected by cross-bridges. In order to analyze subcellular structures in the initial segment, we made serial transverse sections of initial segments of identified chicken motoneurons by retrograde transport of horseradish peroxidase (HRP) injected into the muscle. The mean ( +/-SD) length of the initial segment was 28.1 +/- 2.3 mum (n=6). Mitochondria accumulated in the distal part of the initial segment, which was 1.4-6.9 mum in length (5-23% of the total length of the initial segment). In the transverse section of the distal part, mitochondrial density was 15.8 +/- 6.2% (n=5), while in the middle and proximal parts it was 6.1 +/- 1.6% and 5.6 +/- 1.4%, respectively. Mitochondrial accumulation was observed in common in phasic and tonic motoneurons in the chicken, and also observed in the distal part of the initial segment of the large ventral horn neurons of the chicken without HRP injection. These findings suggest that accumulated mitochondria play an important role in maintaining the physiological function of the distal part of the motoneuron initial segment. (C) 2004 Elsevier B.V. All rights reserved.