Summary
Specialized intercellular junctions in astrocytes and ependymal cells as well as choroid plexus epithelium of the rat were examined with the freeze-fracture or -etch technique. Gap junctions usually showed a discontinuous distribution around the perimeters of astrocytes and ependymal cells, and were composed of closely aggregated particles in fracture face A and polygonally oriented pits in face B. Tight junctions were not usually observed in astrocytes and ependymal cells, but were evident in the choroid plexus epithelium as a ramifying complex of ridges and furrows. This network formed a continuous band on the lateral walls of the plexus epithelial cells. An isolated complex of ridges and furrows, probably a fascia occludens, was rarely found in the ependymal cells of the rat lateral ventricle.
A membrane specialization, described as the ciliary necklace, was seen in the basal region of the ependymal cilia, and was usually composed of 5 or 6, but sometimes of up to 13 strands. Each strand was oriented perpendicularly to the axis of the ciliary shaft and consisted of rows of particles in faces A and B.
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Tani, E., Ikeda, K., Nishiura, M. et al. Specialized intercellular junctions and ciliary necklace in rat brain. Cell Tissue Res. 151, 57–68 (1974). https://doi.org/10.1007/BF00222034
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DOI: https://doi.org/10.1007/BF00222034