Early development of the human area postrema and subfornical organ

Abstract

The first appearance and early development of two circumventricular organs, the area postrema (AP) and the subfornical organ (SFO), were investigated in human embryos and fetuses from the 4th to the 40th gestational weeks (GW). The AP appears very early in development, during the GW 10; its high vascularization can be seen from GW14, and differentiated neurons are observed from GW 16. The SFO is characterized by a late onset of development. It can first be distinguished at GW 17, but it does not attain cytological differentiation until the last weeks of gestation. It is suggested that the AP has important functions during fetal life, which are related to normal fetal weight and growth; in contrast the SFO, which is connected with drinking behavior and salt/water balance, seems to play a less essential role in early fetal life.

Angiotensin II, Vasopressin, and Collagen-IV Expression in the Subfornical Organ in a Case of Syndrome of Inappropriate ADH

“…Several authors have also described the detection of tyrosine hydroxylase-immunoreactivity and vasopressin mRNA and ANGII in the hypothalamus that could be related to hypertension and SIADH [11][12][13][14]. Furthermore, the subfornical organ (SFO) is a circumventricular organ located in the medial plane, below the commissure of fornix (Figures 1(a) and 1(b)), which contains neurons, glia, and a dense plexus of highly fenestrated capillaries, and is covered by an ependymal layer [15,16]. Like other circumventricular organs, the SFO is characterized by the absence of a blood-brain barrier and the presence of tanycytes capable of transporting substances between the cerebrospinal fluid and plasma [15,16].…”

“…Furthermore, the subfornical organ (SFO) is a circumventricular organ located in the medial plane, below the commissure of fornix (Figures 1(a) and 1(b)), which contains neurons, glia, and a dense plexus of highly fenestrated capillaries, and is covered by an ependymal layer [15,16]. Like other circumventricular organs, the SFO is characterized by the absence of a blood-brain barrier and the presence of tanycytes capable of transporting substances between the cerebrospinal fluid and plasma [15,16]. The SFO function is connected with cardiovascular regulation and salt water balance, and the increase of plasma vasopressin is regulated by the SFO angiotensinergic stimulus [9,10,17].…”

Hypertension effects on p73 expression in the rat circumventricular organs and cerebrospinal fluid

“…The human SCO has a great development during the foetal life [8,9], variations in the CSF and SCO have been reported in different kinds of hydrocephalus [4,10,11]. Alterations of the SCO in hydrocephalic mice and rats have been described, Takeuchi et al [12] de-scribes agenesis of the SCO and the posterior commissure (PC) in hydrocephalic mice, Irigoin et al [11], Rodriguez et al [4] and Carmona-Calero et al [7] found alterations in the secretion of the SCO in induced and spontaneously hydrocephalic rats.…”

“…The Subfornical Organ (SFO) is a circumventricular organ located below the commissure fornici, entering the rostral wall of the third ventricle [13], and is a neurogliovascular structure containing neurons, glia and plexus of fenestrated capillaries. The SFO is characterized by the absence of a blood-brain barrier [14].…”

“…The area postrema located at end of the fourth ventricle under the obex [13] also contains neurons, glia and fenestrated capillaries, and does not have a blood-brain barrier. The AP functions are related with cardiovascular regulation and the catecholaminergic system as well as with the anteroventral region of the third ventricle [17,18].…”