circumventricular organ

Also found in: Acronyms.

cir·cum·ven·tric·u·lar organ

Any of the structures in or near the base of the brain that differ from normal brain tissue in having capillaries that lack the usual blood-brain barrier and thus are not isolated from certain compounds in the blood.
References in periodicals archive ?
Both the SFO and OVLT are known circumventricular organs (CVOs) devoid of the normal blood brain barrier and have been shown to be directly responsive to actions of angiotensin II (AngII) [4, 5].
Oldfield, "Intravenous angiotensin II induces Fos-immunoreactivity in circumventricular organs of the lamina terminalis," Brain Research, vol.
In these circumventricular organs (Figure 6-7), blood from the arteries supplying the brain enters capillary networks consisting of fenestrated capillaries and then returns to the venous circulation via the venous sinuses.
Collister and colleagues reported that selective overexpression of superoxide dismutase (SOD) in one of the circumventricular organs (organum vasculosum of the lamina terminalis, OVLT) via injection of adenoviral vectors encoding human CuZnSOD (SOD1) significantly decreases blood pressure in an AngII-induced rat model of hypertension.