Circumventricular organs: Neuroendocrine interfaces between the brain and the hemal milieu

Abstract

The circumventricular organs (CVOs) of the mammalian brain are the subfornical organ, organum vasculosum of the lamina terminalis (OVLT), median eminence/neurohypophysis, subcommissural organ, pineal gland, area postrema, and choroid plexus. While these CVOs have individual characteristics, they do share a number of common properties that distinguish them from other parts of the central nervous system. Lack of a blood-brain barrier (except for the subcommissural organ) due to the presence of fenestrated capillary endothelium, and extensive perivascular spaces are two such properties and provide some of the morphological basis for neuroendocrine roles of the CVOs. Centrally synthesized hormon..