DISTRIBUTION WITHIN BRAIN OF FERRITIN INJECTED INTO CEREBROSPINAL FLUID COMPARTMENTS .2. PARENCHYMAL DISTRIBUTION
DISTRIBUTION WITHIN BRAIN OF FERRITIN INJECTED INTO CEREBROSPINAL FLUID COMPARTMENTS .2. PARENCHYMAL DISTRIBUTION
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DOI：
10.1002/aja.1001170204
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发表时间：
1965-01-01
影响因子：
--
通讯作者：
BRIGHTMAN, MW
中科院分区：
文献类型：
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作者：
BRIGHTMAN, MW
脑内相邻细胞突起的质膜之间的电子透明通道，宽约200埃，是铁蛋白分子可以沿其移动的真正的细胞周空间沿着。电子显微镜下可见的胶束在空间中移动，直到它们遇到胶质细胞间融合或其髓鞘对应物。神经胶质突起之间的间隙被这些膜间融合突然封闭，或者偶尔被能够捕获铁蛋白的致密填料扩张。因此，大脑间隙在宽度和内容上变化很大。分子最初通过穿过面向蛛网膜下腔的胶质细胞边缘的基底膜进入间隙，在那里它们被下面的胶质细胞突起胞饮，并且在前髓帆的蛛网膜下腔边缘处，也直接通过相邻的室管膜延伸之间。一旦进入实质间隙，胶束可以被神经元胞体和突起胞饮，并且在更大程度上被胶质纤维胞饮。由较厚的而不是衰减部分的胶质纤维的胞饮作用表明，质膜上的一个过程的相对侧必须分开一个临界距离之前，胞饮压痕可以形成。因此，较薄的部分比较厚的区域对胶束的运动提供更大的屏障。
The electron lucent channels, about 200 A-wide, between the plasmalemmas of adjacent cell processes within the brain are true pericellular spaces along which ferritin molecules can move. The micelles, visualized electronmicroscopically, move through the spaces until they encounter an interglial fusion or its myelin counterpart. The interspace between glial processes is abruptly sealed by these inter-membranous fusions or occasionally distended by a dense filler capable of trapping ferritin. The cerebral interspace is thus highly variable in width and content. Molecules initially enter the interspace by passing across the basement membrane of the glial border fronting the subarach-noid space whence they are pinocytosed by the underlying glial processes and, at the subarachnoid border of the anterior medullary velum, by also passing directly between adjacent ependymal extensions. Once having entered the parenchymal interspace, micelles can be pinocytosed by neuronal somata and processes and, to a greater degree, by glial fibers. Pinocytosis by the thicker rather than the attenuated portions of glial fibers suggests that the plasmalemmas on the opposite sides of a process must be separated by a critical distance before pinocytotic indentations can be formed. The thinner portions thus offer greater barriers to the movement of micelles than do thicker regions.