A Golgi-Cox study of tanycytes in the hypothalamic region of the third ventricle in the wild rat, Rattus rattus rattus (L.).

In the third ventricle of the wild rat, Golgi-Cox-positive tanycytes of varied shape and size are arranged with their perikarya in the ependymal layer and basal processes extending into the core of the subependyma. The basal processes may be smooth and slender, or barbed and branching, and often take circuitous and overlapping courses. In some, the apical part of the perikaryon projects into the ventricle. In the arcuate region, groups of closely arranged tanycytes whose long basal processes end on the arcuate neurons and the portal vessels in the tubero-infundibular sulci are noticed. The tanycytic processes of the median eminence terminate on the portal vessels in the palisade layer. Some tanycytic processes of the mammillary recess even extend up to the ventral surface of the brain and have disc-like terminations.