The Sheep Third Ventricle: Scanning Electron Microscopy of Estrous, Anestrous and Estrogen-Progesterone-Treated Anestrous Ewes

• Published in: Biology of reproduction Vol. 17; no. 4; pp. 567 - 573
• Main Authors: Coates, P W, Davis, S L
• Format: Journal Article
• Language: English
• Published: United States Society for the Study of Reproduction 01-11-1977
• Subjects: Anestrus - drug effects; Animals; Cell Membrane - drug effects; Cell Membrane - ultrastructure; Cerebral Ventricles - drug effects; Cerebral Ventricles - ultrastructure; Ependyma - drug effects; Ependyma - ultrastructure; Estradiol - pharmacology; Estrus; Female; Pregnancy; Progesterone - pharmacology; Sheep
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod17.4.567

Surface features of the third ventricle in estrous, anestrous and anestrous estrogen-progesterone
(E 2 +P)-treated ewes were examined with scanning electron microscopy (SEM). To ensure uniformly good preparations, a procedure
for rapid perfusion of sheep brains was developed as well as the
use of critical point drying. Ependymal surfaces on the dorsal aspects of the lateral walls as viewed
by SEM were heavily ciliated while the ventral aspect of the lateral walls and ventral floor were
not. In all groups, the appearance of the lateral walls was similar while that of the ventral floor-median eminence appeared
to vary with the absence or presence of gonadal steroids. In estrous ewes
there were numerous stubby microvilli and miniblebs on ependyma of the ventrolateral wall-floor,
many of which are presumed to be tanycytes. This contrasted with the appearance of similar regions in anestrous ewes where
there were patchy smooth bare areas on ependymal surfaces with
fewer microvilli and small surface protrusions. Anestrous E 2 +P-treated ewes showed an appearance
intermediate between the other two groups. The SEM data support a correlation between reproductive status and the relative
presence or absence of surface modifications on the ventral floor of
the sheep third ventricle.