Comportamiento de los órganos circunventriculares en la hipertensión sistémica. Revisión.

Abstract

Circumventricular organs are composed of specialized epidermis with active pinocytosis. They are located mainly in the middle portion of the brain, in a strategic position of the ventricular surface. They have the characteristic of possessing abundant networks of capillaries that, except those located in the subcommissural organ (OSC), lack a blood-brain barrier, since there is a labyrinth-like pericapillary space surrounding the fenestrated capillaries. They belong to the circumventricular organs, the Median Eminence (EM), the Supraoptic Ridge or Vascular Organ of the lamina terminalis (OVLT), the Subcommissural organ (OSC), the Subfornical Organ (OSF). Recently, the choroid plexus (PC), the pineal gland (GP), and the neurohypophysis (HY) are also included as circumventricular organs. Hypertension affects OCV differently; it seems that certain OCVs such as: OSC, PC, and AP, the variations found could be an effect of the vascular alterations and of the hypertension and ventriculomegaly cerebral barriers described in the SHR rat. But in other OCV such as OSF, OVLT, EM and NH the variations appear to be prior to the occurrence of hypertension in SHR, and these alterations could be part of the causes and not consequence of the hypertension described in the spontaneously hypertensive rat.