The neuroactive neurosteroid Dehydroepiandrosterone Sulfate (DHEAS) modulates the serotonergic system within the dorsal Raphe nucleus and the cerebrospinal fluid release of Reissner’s fiber in rat

Abstract

Dehydroepiandrosterone sulfate (DHEAS) exerts important functions in the nervous system, such as modulation of neuronal death, brain development, cognition and behavior. However, little is known about the possible interactions of this steroid with the glial cells, in particular those forming circumventricular organs (CVOs). The present study, on the one hand, was focused on the assessment of the possible effect of DHEAS on the subcommissural organ in rats. Known as one of the CVOs, the SCO can release a glycoprotein of high molecular weight named Reissner’s fiber (RF) into the cerebrospinal fluid (CSF), a remarkable secretory activity. On the other hand, we examined the serotonergic innervation in the Dorsal Raphe nucleus (DRN) and the subsequent SCO. Our finding has revealed a significant increase in RF immunoreactivity within the SCO following a single i.p injection of DHEAS at a dose of 5 mg/kg B.W. A loss of serotonin (5-HT) within the DRN and fibers reaching the SCO was also observed. The present findings have brought evidence of a possible modulator potential of neurosteroids, in particular DHEAS, upon the secretory activity of the SCO. This study will open a new window for a better understanding of the main role and interaction of neurosteroids with one of the relevant circumventricular organs in the mammalian brain.

Keywords

• Dehydroepiandrosterone sulfate (DHEAS)
• Rat
• Circumventricular organs
• Subcommissural organ
• Reissner’s fiber
• Serotonin