Morphology of the pineal gland in opossum (Didelphis sp)

Abstract

The pineal gland must to be analyzed and studied in animals of the Brazilian fauna, to apply the data obtained in the basic research of new techniques at reproductive handling of these animals, including in captivity, in view of the close relation between this photoreceptor organ with the circadian and reproductive cycle. For this study, 10 opossums (Didelphis sp), had been used, already died and fixed, proceeding from the Department of Anatomy of USP and UNIFEOB. None animals were submitted to pain/suffering situations and their no life sacrifice. The pineal gland was found in all studied animals with and smaller dimention, not possessing, therefore goss features. By microscopy analysis we could found the gland in the correspondent space to median plan in relation to the encephalon, rostral and dorsally to the rostral coliculli, ventrally to the brain hemispheres and caudally to the habenular comissure. That consistes like an evagination of the diencephalons tectum showing the "U" shape. Considering other pineal glands and its features in different species, we note the gland is extremely small for it specie, possessing dispersed secretory cells in the nervous parenchyma whose form, sufficiently irregular, suggests a small hormonal performance to them in the Didelphis genus. Comparativelly of the pineal gland feactures in different animals, the Didelphis genus, that was our aim, shows pecualirity as in size relation, only microscopically visible, than the fact to prossessing similar secretory cells also dispased in neighbor areas. All pecualiarites suggest refletion about the function action of the gland at the studied specie.