Summary
Tanycytes along the third ventricle have been studied in adult rat and mouse brains with the rapid Golgi method. A tanycyte can be divided into three portions: somatic, neck, tail. The somatic portion is in the ependymal layer and frequently has thin cytoplasmic extensions. The neck portion originates from the soma and sticks into the periventricular layer. It, too, has numerous fine lamellar processes radiating from it. The neck contacts a blood vessel. Distal to this contact, the neck becomes thin and devoid of its cytoplasmic processes. This is the tail portion, which courses through hypothalamic nuclei to terminate as small bulbous swellings either on a vessel or at the pial surface.
Although tanycytes occur throughout the dorsoventral extent of the ventricle, they are especially numerous ventrally. Midway down the ventricular wall, the neck processes interdigitate and form a moderately loose fabric beneath the ependyma. Proceeding ventrally, this becomes denser and thicker.
Because the tails have no apparent associations with cells in the hypothalamic nuclei, the functional interactions of tanycytes with hypothalamic neuropil are probably confined to the periventricular layer.
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Supported by: NINDS Grants 5 RO1 NS 09001-02 NEUA, 5 TO1 NB 5309, and GM 00958, and by the Eleanor Roosevelt Cancer Foundation Research Institute.
It is a pleasure to acknowledge the expert photographic assistance of Mr. Keith Johnson.
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Millhouse, O.E. A Golgi study of third ventricle tanycytes in the adult rodent brain. Z. Zellforsch. 121, 1–13 (1971). https://doi.org/10.1007/BF00330913
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DOI: https://doi.org/10.1007/BF00330913