CHANGES IN DENDRITIC MORPHOLOGY OF RAT SPINAL MOTONEURONS DURING DEVELOPMENT AND AFTER UNILATERAL TARGET DELETION
CHANGES IN DENDRITIC MORPHOLOGY OF RAT SPINAL MOTONEURONS DURING DEVELOPMENT AND AFTER UNILATERAL TARGET DELETION
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DOI：
10.1016/0165-3806(93)90133-u
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发表时间：
1993-06-08
期刊：
影响因子：
--
通讯作者：
SENGELAUB, DR
中科院分区：
文献类型：
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作者：
GOLDSTEIN, LA;KURZ, EM;SENGELAUB, DR
在正常发育过程中，球海绵体肌脊髓核（SNB）中的运动神经元树突旺盛生长，几乎是成年长度的两倍，然后缩回。在这项研究中，我们逆行标记的SNB运动神经元与霍乱毒素B-结合辣根过氧化物酶（BHRP），以研究SNB树突状乔木的成熟更详细，特别是关于其空间分布和重组。SNB运动神经元初级突起的数量和方向在出生后的前10周内没有变化。相反，总树突长度，径向范围和乔木面积显着增加，通过出生后的前4周，此后下降。长度和范围的下降仅限于特定部分的乔木，特别是背侧，同侧和对侧的预测。从两侧的SNB的树突状乔木之间的重叠程度的估计反映了这些变化，重叠最初增加，然后减少的SNB建立其成人树突状形态。为了确定这种乔木重叠促进树突的相互作用可能参与调节SNB树突的正常收缩，我们减少了SNB运动神经元的数量单方面的目标肌肉去除出生当天。在单侧肌肉摘除动物中，初级突起的体积、数量和方向发育正常。幸存的SNB运动神经元在单侧肌肉摘除男性的树突形态发生了改变，树突的长度，范围和乔木面积相对于正常男性显着增加。这些结果表明，SNB运动神经元的树突组织的实质性变化发生在正常的发展，并可能受到树突之间的相互作用，从两个半的SNB。
During normal development, motoneuron dendrites in the spinal nucleus of the bulbocavernosus (SNB) grow exuberantly to almost twice their adult length and then retract. In this study, we retrogradely labeled SNB motoneurons with cholera toxin B-conjugated horseradish peroxidase (BHRP) to examine the maturation of SNB dendritic arbors in more detail, particularly with regard to its spatial distribution and reorganization. The number and orientation of SNB motoneuron primary processes did not change over the first ten weeks of life. In contrast, total dendritic length, radial extent and arbor area increased significantly through the first four postnatal weeks and declined thereafter. The declines in length and extent were restricted to particular portions of the arbor, specifically the dorsal, ipsi- and contralateral projections. Estimates of the degree of overlap between the dendritic arbors from both sides of the SNB reflected these changes, with overlap initially increasing and then decreasing as the SNB established its adult dendritic morphology. To determine if dendritic interactions facilitated by this arbor overlap might be involved in regulating the normal retraction of SNB dendrites, we reduced SNB motoneuron numbers unilaterally by target muscle removal on the day of birth. Somal size, number and orientation of primary processes developed normally in unilateral muscle-extirpated animals. The dendritic morphology of surviving SNB motoneurons in unilateral muscle extirpated males was altered, with significant increases in dendritic length, extent and arbor area relative to those of normal males. These results indicate that substantial changes in dendritic organization of SNB motoneurons occur in normal development and may be influenced by interactions between dendrites from the two halves of the SNB.