title: Different vascular permeability between the sensory and secretory circumventricular organs of adult mouse brain.
abstract: The blood-brain barrier (BBB) prevents free access of circulating molecules to the brain and maintains a specialized brain environment to protect the brain from blood-derived bioactive and toxic molecules; however, the circumventricular organs (CVOs) have fenestrated vasculature. The fenestrated vasculature in the sensory CVOs, including the organum vasculosum of lamina terminalis (OVLT), subfornical organ (SFO) and area postrema (AP), allows neurons and astrocytes to sense a variety of plasma molecules and convey their information into other brain regions and the vasculature in the secretory CVOs, including median eminence (ME) and neurohypophysis (NH), permits neuronal terminals to secrete many peptides into the blood stream. The present study showed that vascular permeability of low-molecular-mass tracers such as fluorescein isothiocyanate (FITC) and Evans Blue was higher in the secretory CVOs and kidney as compared with that in the sensory CVOs. On the other hand, vascular permeability of high-molecular-mass tracers such as FITC-labeled bovine serum albumin and Dextran 70,000 was lower in the CVOs as compared with that in the kidney. Prominent vascular permeability of low- and high-molecular-mass tracers was also observed in the arcuate nucleus. These data demonstrate that vascular permeability for low-molecular-mass molecules is higher in the secretory CVOs as compared with that in the sensory CVOs, possibly for large secretion of peptides to the blood stream. Moreover, vascular permeability for high-molecular-mass tracers in the CVOs is smaller than that of the kidney, indicating that the CVOs are not totally without a BBB.
authors.affiliation: Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Morita
authors.forename: Seiji
authors.initials: S
authors.lastname: Miyata
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism*; D001921:Brain / Q000098:blood supply* / Q000378:metabolism; D002199:Capillary Permeability; D002417:Cattle; D003911:Dextrans / Q000737:chemistry / Q000493:pharmacokinetics; D005070:Evans Blue / Q000493:pharmacokinetics*; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry / Q000493:pharmacokinetics*; D007668:Kidney / Q000098:blood supply / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009490:Neurosecretory Systems / Q000098:blood supply* / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D003911:Dextrans; D012710:Serum Albumin, Bovine; D005070:Evans Blue; D016650:Fluorescein-5-isothiocyanate