An un usual course of the Nervus Conarii in the pineal glandof the tinamid bird Crypturellus parvirostris. A case report

The pineal gland is innervated by postganglionic sympathetic nerves from the superior cervical ganglion. As theaxons enter the gland, they synapse with the pinealocytes. In this report, we describe a case in which the conarii nervewas observed crossing the distal portion of the ascending branch of the venous sinus, thus penetrating the capsule ofthe pineal gland. The nerve observed consisted of a bundle of unmyelinated axons and collagen fibers which aresurrounded by endothelial cells. This is the first report of a completely engulfed and detached conarii nerve within avenous sinus.

Ultrastructure of the pineal gland in Akodon arviculoides cursor (Rodentia: Cricetidae): a quantitative study of dense-core vesicles

The pineal gland of Akodon arviculoides cursor shows a saccular pattern of organization with a wide and irregular lumen outlined by cuboidal and columnar epithelial cells. This feature was never reported before, in literature, among mammals. the pinealocytes are clustered together in the periphery of the organ and can be distinguished as light and dark cells. These cells show great amounts of mitochondria, microtubules, polysomes and a few dense-core vesicles. Higher amounts of dense-core vesicles are present in pinealocytes of young animals than in adult ones. In spite of the sacccular and follicular patterns of organization, that are considered a more primitive aspect of the gland, we could not observe, in this species, outer segments in the pinealocytes, which characterize the photoreceptor cells of the pineal organ in lower vertebrates.

The effects of castration on the dense-core vesicles and lysosomes of pinelacoytes in male adult mice: a quantitative study

The dense-core vesicles and lysosomes of the adult mice pinealocytes has been studied during normal and experimental (castrated) conditions. Twelve male animals were studied and divided into two groups of six animals: a control group and a castrated one. In all the specimens the dense-core vesicles and lysosomes were counted in a total area of 2,764.80 µm2 of pineal tissue. In adult mice the pineal gland shows dense clusters of light and dark pinealocytes in a distinct rosette-like arrangement. The perinuclear region and cytoplasmic processes of these cells have a moderate distribution of lysosomes and dense-core vesicles. The castrated animals showed a decrease in the number of lysosomes and an increase in the number of dense-core vesicles. Thus, it appears from the present results that the testicular androgens play an inhibitory function on the secretory activity of pinealocytes.

Estudo morfológico do órgäo pineal do rato-espinho Proechimys iheringi Thomas, 1911 / Morphological study of the pineal organ in the spined rat proechimys iheringi Thomas, 1911

O órgäo pineal do rato-espinho está situado profundamente próximo ao terceiro ventrículo. Possui um padräo de organizaçäo compacto, com pinealócitos e astrócitos formando cordöes ou rosetas. Numerosas concreçöes hematoxilina alúmen-crômica positivas estäo presentes no tecido adjacente à pineal e às veias que drenam este órgäo. Neste trabalho é discutida a provável origem destas concreçöes

Estudo morfométrico do órgäo pineal de Crypturellus parvirostris (Aves; Tinamiformes) em diferentes fases do ciclo sexual / Morphometric study of the pineal organ in Crypturellus parvirostris (Aves; Tinamiformes) during different phases of sexual cycle

Com a finalidade de determinar variaçöes morfológicas do órgäo pineal relacionadas com diferentes períodos da reproduçäo, foram comparados aspectos morfométricos da pineal de aves em reproduçäo e de aves reprodutivamente quiescentes. Assim, as pineais de aves em reproduçäo mostraram maior volume dos folículos e das células foliculares e maior volume e diâmetro médio dos núcleos das células foliculares. As células foliculares das pineais de aves reprodutivamente quiescentes mostraram maior volume citoplasmático. Estes resultados mostram que a pineal de Crypturellus parvirostris apresenta mudanças sazonais possivelmente relacionadas às modificaçöes do seu ciclo reprodutivo