Circumventricular organs

Babu GN, Bawari M, Ali MM Lipid-peroxidation potential, antioxidant status of circumventricular organs of rat brain following neonatal monosodium glutamate. Neurotoxicology 15 773-777, 1994... 

In contrast to MAO-A mRNA, the distribution of MAO-B mRNA in the brain was very circumscribed. There were only three brain regions in which the amount of MAO-B mRNA exceeded the limits of detection the area postrema, the dorsal raphe, and the subfornical organ. The area postrema and the subfornical organ are both circumventricular organs that contain a wide... 

The BBB is found throughout the brain and spinal cord except for a small number of isolated regions of brain that line the ventricles, the large cavities in the middle of the brain. These circumventricular organs (CVOs) include the choroid plexus (a patch of tissue that lines the floors of the ventricles and manufactures cerebrospinal fluid), the median eminence of the hypothalamus, the subfornical organ at the roof of the third ventricle and the area postrema at the base of the fourth ventricle. 

Bruni, J.E., Bose, R., Pinsky, C., and Glavin, G. 1991. Circumventricular organ origin of domoic acid-induced neuropathology and toxicology. Brain Res Bull 26, 419-424. 

The BBB is not a single barrier, but several barriers, which are in parallel. This contrasts with the testis-blood barrier, which consists of several barriers in series. The most studied of these barriers is the vascular barrier and perhaps the least studied are the barriers, that interface between the circumventricular organs (CVO) and the rest of the CNS. 

The CNS of mammals contains seven regions of the brain where the vasculature does not fully participate in a BBB (Gross and Weindl, 1987). These regions have at least one side that faces a ventricle and so are termed circumventricular organs (CVOs). Together, they comprise about 0.5% of the brain by weight. Their capillaries allow the production of an ultrafiltrate and so their cells are in more intimate contact with the circulation. 

Johnson AK, Gross PM (1993) Sensory circumventricular organs and brain homeostatic pathways. FASEB J 7 678-686. 

McKinley M.l. McAllen RM, Mendelsohn FA. O., Allen AM, Chai SY, Oldfield BJ. Circumventricular organs neuroendocrine interfaces between the brain and the hemal milieu. Frontiers in Neuorendocrin-ology. Raven, New York, 1990. Vol. 11, pp. 91-127. 

These effects may be mediated by specific activation of hypothalamic areas known to regulate food intake and body weight and which express the CNTFRa (Fig. lA). Several of these brain areas, such as the arcuate nucleus, are accessible from the periphery due to their proximity to circumventricular organs, whose capillaries... 

CNS. There have been studies in which Glu, often in the form of MSG, has been injected subcutaneously to neonatal mice or nonhuman primates and hypothalamic lesions noted. The lesions are mostly restricted to the circumventricular organs (those near the fourth ventricle), where the blood-brain barrier is significantly diminished. Additionally, when MSG is directly injected into the brains of laboratory animals, cellular necrosis is observed. When MSG is given in very high doses orally, however, the homeostatic processes in liver and other... 

Blood-brain barrier (BBB), one barrier separating the central nervous system (CNS) from the periphery, located at the endothelial cells of the brain tissue capillaries besides the blood-cerebrospinal fluid barrier (B-CSF-B) at the choroid plexus and the circumventricular organs. Peptides and protein drugs are generally excluded from transport from blood to brain. However, a chimeric peptide strategy for peptide drug delivery allows the delivery of... 

Swiss-Webster circumventricular organs and their environs ... 

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