AN ELECTRON MICROSCOPIC STUDY OF NEURONS DURING POSTNATAL DEVELOPMENT OF RAT CEREBRAL CORTEX
AN ELECTRON MICROSCOPIC STUDY OF NEURONS DURING POSTNATAL DEVELOPMENT OF RAT CEREBRAL CORTEX
复制标题
DOI：
10.1002/cne.901330103
复制
发表时间：
1968-01-01
影响因子：
2.5
通讯作者：
MAXWELL, DS
中科院分区：
文献类型：
--
作者：
CALEY, DW;MAXWELL, DS
用光镜和电镜观察了出生后3周大鼠大脑皮层神经元的分化和成熟情况。出生时，浅层皮层主要由未分化的细胞组成，它们紧密地排列在垂直的柱状结构中，柱状结构之间有发育过程和血管，以及相对广泛的细胞外空间。在前两周，这些细胞分化为成神经细胞和神经元，或成海绵状细胞和神经胶质细胞。在神经元而不是神经胶质的情况下，这种成熟发生在从深度到表面的梯度中。圆形未分化细胞的特征是没有突起，核周细胞质的薄边缘含有很少的细胞器，周围有浓缩核染色质团块。分化中的神经母细胞显示细胞器数量增加，尤其是内质网，核染色质分布均匀，推测顶端树突。成神经细胞粗面内质网在第二周转变为神经元时肿胀。内质网形成表面下池，瞬时外翻细胞膜，在神经细胞内形成明显的憩室，同时细胞显示细胞质基质密度增加，核糖体数量增加。在出生后的3周内，细胞器的数量和复杂性增加，突触发育，细胞外空间消失，成熟的神经元因神经细胞和非神经细胞的生长而彼此分离。3周后，皮层组织及其神经元明显成熟，皮层精细结构形成成体模式。
The differentia-tion and maturation of the neurons of rat cerebral cortex during the first 3 weeks of postnatal life has been studied with the light and electron microscopes. At birth, the superficial cortex is largely made up of undifferentiated cells, tightly packed together in vertical columns between which the developing process and blood vessels, and relatively extensive extracellular spaces are found. During the first two weeks, these cells differentiate into either neuroblasts and neurons, or into spongioblasts and neuroglia. In the case of neurons but not neuroglia, this maturation occurs in a gradient from the depths toward the surface. The round undifferentiated cells are characterized by an absence of processes, a thin rim of perinuclear cytoplasm containing few organelles, and a peripheral clumping of condensed nuclear chromatin. The differentiating neuroblasts display increasing numbers of cytoplasmic organelles, especially endoplasmic reticulum, evenly dispersed nuclear chromatin, and presumptive apical dendrites. The rough endoplasmic reticulum of neuroblasts become swollen during the transition into neurons during the second week. The endoplasmic reticulum forms subsurface cisterns that transiently evaginate the cell membrane, forming conspicuous diverticuli in the neuropil at the same time that the cells display an increase of cytoplasmic matrix density and increasing numbers of ribosomes. During the 3 weeks following birth, organelles increase in number and complexity, synapses develop, the extracellular spaces disappear, and the maturing neurons become separated from one another by the growth of neuropil and nonnervous elements. At the end of this 3 week period the cortical tissue and its neurons are apparently mature and the adult pattern of cortical fine structure is established.