IS THE HUMAN AREA POSTREMA A NEURO-VEGETATIVE NUCLEUS?

Abstract

The structure of the area postrema in the floor of the human 4th ventricle was examined in 7 brains by serial section and Bodian''s silver impregnation method, and in other brains by Heidenhain''s iron hematoxylin and other methods. The nerve cells contain a varying amt. of melanin pigment and often show a gland-like grouping in close relation to the sinusoids. A well-developed plexus of nerve fibers encircles the melanotic cells and the vessels and is frequently continued into the ependyma covering the area postrema. The fibers are connected with the subependymal nerve plexus in adjacent regions, pass via the teniae to the opposite side, and often show bud-like endings. These findings, along with the presence of mast cells, suggest that, besides controlling the diffusion of substances from the blood into the cerebrospinal fluid as suggested by Wislocki and Putnam, the area postrema may regulate the blood supply of the rhombencephalon. Structural similarity with the vegetative cell groups of the diencephalon suggests that the cells of the area postrema have a neuro-secretory function.