The subcommissural organ ofPodarcis s. siculaRaf. A model for functional studies

Abstract

This study concerns the subcommissural organ (SCO) of Podarcis s. sicula Raf. in normal and experimentally treated animals. SCO cells present a secretory cycle during the year, with maximum secretion in summer and minimum in winter. SCO secretory activity parallels the sexual cycle in this lizard. The secretory activity of this organ is influenced by all experimental procedures that affect Leydig cells and the SCO. Experimental evidence suggests a relationship between the SCO and the adrenal gland. Indeed, there is an increase in the secretory material of SCO cells with treatment that induces an increase of testosterone or adrenal gland activity in the organism. Vice versa, treatment that leads to a decrease in hormones or that blocks their effects, also brings about a decrease in the amount of secretory material in the SCO.All the data obtained show that both steroid hormones and thermic factors are involved in the control of SCO secretory activity.

Microscopic anatomy of the subcommissural organ in the brain of the adult greater cane rat (Rodentia: Thryonomyidae)

“…The subcommissural organ (SCO) in the brain (encephalon) is a highly secretory component of circumventricular organs, made up of a specialized ependymal brain gland positioned in the boundary between the forebrain and midbrain (diencephalic part). It forms the dorsal part of the third ventricle and its embryonic origin is from the dorsal midline layer of neuroepithelial cells just ventral to the posterior commissure (PC) (D'uva & Varano, 1988; Inada et al., 2023). From both light and electron microscopic studies, it has been established that the specialised ependymal gland (SCO cells) releases a secretion into the cerebrospinal fluid (CSF) in the ventricle (Guerra et al., 2015) where most of it aggregates to form a thread‐like, filamentous structure known as Reissner's fibre (RF) (Muñoz et al., 2018; Reissner, 1860).…”