EARLY PATTERN OF NEURONAL DIFFERENTIATION IN THE XENOPUS EMBRYONIC BRAIN-STEM AND SPINAL-CORD
EARLY PATTERN OF NEURONAL DIFFERENTIATION IN THE XENOPUS EMBRYONIC BRAIN-STEM AND SPINAL-CORD
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DOI：
10.1002/cne.903280205
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发表时间：
1993-02-08
影响因子：
2.5
通讯作者：
HARTENSTEIN, V
中科院分区：
文献类型：
--
作者：
HARTENSTEIN, V
采用全抗体标记技术和辣根过氧化物酶标记技术，分析了非洲爪蟾胚胎中枢神经系统在22和35/36期之间的神经元分化模式。在脊髓中，首先分化的神经元是Rohon-Beard神经元;随后是具有下行轴突的腹侧神经元（下行中间神经元，运动神经元）和具有连合轴突的侧中间神经元。这些初级神经元的胞体和轴突分别形成背柱、腹柱和侧柱;腹柱和侧柱不间断地向前延伸到脑干。定量分析脊髓神经元的分布和投射方式。Rohon-Beard神经元、连合中间神经元和初级运动神经元的数量在节段之间变化。因此，这些神经元不是以节段模式分布的。在每个节段中，给定类型的神经元投射轴突，其长度在很大范围内变化。计算由给定类型的神经元群体形成的轴突长度的数值分布，并表示为这些神经元的投影轮廓。对于每种类型的神经元和脊髓节段，投影轮廓是不同的。此外，投影轮廓沿着脊髓以系统的方式变化。例如，如果向尾侧脊髓水平移动，则具有长的上行轴突的Rohon-Beard神经元的比例稳步增加。研究结果表明，超节段线索与分级分布沿着脊髓确定的数量和投影轮廓的特定细胞类型在一个给定的部分。
Wholemount antibody labeling techniques and horseradish peroxidase backfilling were used to analyze the pattern of neuronal differentiation in the embryonic Xenopus central nervous system between stages 22 and 35/36. In the spinal cord, the first neurons to differentiate are the Rohon-Beard neurons; they are followed by ventral neurons with descending axons (descending interneurons, motoneurons) and lateral interneurons with commissural axons. The somata and axons of these primary neurons form dorsal, ventral, and lateral columns, respectively; the ventral and lateral columns uninterruptedly continue forward into the brainstem. The distribution and projection patterns of spinal neurons were analyzed quantitatively. Rohon-Beard neurons, commissural interneurons, and, primary motoneurons vary in number from segment to segment. Thus, these neurons are not distributed in a segmental pattern. In each segment, neurons of a given type project axons whose length varies over a wide range. The numerical distribution of length of axons formed by a population of neurons of a given type was calculated and expressed as the projection profile of these neurons. For each type of neuron and spinal segment, the projection profile is different. Furthermore, the projection profiles change in a systematic way along the spinal cord. For example, the fraction of Rohon-Beard neurons with long ascending axons steadily increases if one moves towards caudal spinal levels. The findings suggest that suprasegmental cues with a graded distribution along the spinal cord determine the number and projection profile of a particular cell type in a given segment.