circumventricular organs


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cir·cum·ven·tric·u·lar or·gans

four small areas in or near the base of the brain that have fenestrated capillaries and are outside the blood-brain barrier. They are the neurohypophysis, the area postrema [TA], the organum vasculosum of the lamina terminalis [TA], and the subfornical organ [TA]. The neurohypophysis is a neurohemal organ. The other three are chemoreceptors: the area postrema triggers vomiting in response to chemical changes in plasma, the organum vasculosum of the lamina terminalis senses osmolality and alters vasopressin secretion, and the subfornal organ initiates drinking in response to angiotensin II.

cir·cum·ven·tric·u·lar or·gans

(sĭr'kŭm-ven-trik'yū-lăr ōr'gănz)
Four small areas at the base of the brain that are outside the blood-brain barrier. They are neurohypophysis, area postrema, organum vasculosum of the lamina terminalis, and subfornical organ (SFO).
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.
Simpson, "The circumventricular organs and the central actions of angiotensin," Neuroendocrinology, vol.
Past experiments in which researchers had elecrically stimulated various circumventricular organs in the brain of mice, including the SFO, had yielded inconsistent results.
The circumventricular organs are chemosensitive cells that are highly innervated with fenestrated capillaries.
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.
Particular attention should be paid to lesions in circumventricular organs and the optic nerve head, since in both regions the blood-brain barrier is less tight than in other regions of the CNS, and AQP-4 is highly expressed at these sites.
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.