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Fine structure and its functional properties of the ependymal cell in the frog median eminence

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Summary

Intercellular canaliculi surrounded by several ependymal cells, having numerous microvilli and a few cilia on the apical surface, are present throughout the frog median eminence. The intercellular canaliculi penetrate deeply near the portal vessel from the third ventricle. They are separated from the pericapillary space only by the thin cytoplasm of the ependymal cell.

The cytoplasmic protrusions containing a large number of clear vesicles are often found at the apical surface of ependymal cells facing the third ventricle or the lumen of intercellular canaliculus. The ependymal cell shows well developed Golgi apparatus and well developed rough endoplasmic reticulum in its cytoplasm. Dense granules of about 1200–1500 A diameter suggesting secretory materials are found in small number near the Golgi apparatus and abundantly in the ependymal process lying around the portal vessel.

Synaptic contacts between the ependymal cell and two different types of the nerve endings, monoaminergic and peptidergic, are frequently observed. A few small flasklike caveolae suggesting micropinocytosis are found in the post-synaptic membrane as well as in the lateral and basal plasma membranes of the ependymal cell. The author consideres that the ependymal cell in this region has secretory and transport (absorption) activities.

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  1. Department of Anatomy, Hiroshima University School of Medicine, Kasumicho, 734, Hiroshima, Japan

    Yasumitsu Nakai

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  1. Yasumitsu Nakai
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Nakai, Y. Fine structure and its functional properties of the ependymal cell in the frog median eminence. Z.Zellforsch 122, 15–25 (1971). https://doi.org/10.1007/BF00936113

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  • DOI: https://doi.org/10.1007/BF00936113

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