[Vascular characteristics of the human subfornical organ]

The aim of the study regarding adult brains is to determine the sources of vascularization, vascular area, the size and density of the capillary network of the human subfornical organ. The examined brain blood vessels under filled with a mixture of Indian ink and gelatin. The serial paraffin sections of 50 and 200 microns were cleared after Spalteholz. In the vascularization of this neuroendocrine structure of the diencephalon, two arterial stems take part with their branches: a. cerebri anterior and a. choroidea posterior. In order to quantify the density of the capillary network, the authors used the standard stereologic parameters volume density, surface density and mean radius of blood vessels. By the comparative test of obtained mean values of males and females no statistically significant differences pertaining to sex and in respect to the size and density of capillary network in subfornical organ were confirmed. While the precise functions of the human subfornical organ have yet to be fully elucidated, the similarity in organization of this region to the vascular organ of the lamina terminalis, has led several authors to suggest that the subfornical organ is a site of receptors which are stimulated by circulating angiotensin II to induce water drinking and vasopressin secretion.