title: Ontogeny of four blood-brain barrier markers: an immunocytochemical comparison of pial and cerebral cortical microvessels.
abstract: Pial and cortical microvessels possess many blood-brain barrier (BBB) properties in common, including impermeability to electron dense tracers, high transendothelial electrical resistance and specialised endothelial cell ultrastructural features. To compare pial and cortical microvessels further, a developmental, immunocytochemical study was undertaken of 4 BBB markers in the rat: OX-47, EBA, GLUT-1 and s-laminin. The appearance of the markers was monitored from embryonic d 16, to postnatal and adult stages. Each of the 4 markers appeared simultaneously in both pial and cortical vessels. GLUT-1 and OX-47 were present in endothelial cells of the BBB from E 16 to the adult. EBA and s-laminin appeared from postnatal d 7 through to the adult. Pial microvessels lack the ensheathment of astrocytes which may be involved in the induction and/or maintenance of BBB markers in the cortex. It is possible that astrocyte-derived factors diffusing from the brain surface are responsible for induction of BBB properties in the pial microvessels.
authors.affiliation: Department of Anatomy and Cell Biology, Imperial College School of Medicine at St Mary's, London, UK.
authors.forename: J P
authors.initials: JP
authors.lastname: Cassella
authors.forename: J G
authors.initials: JG
authors.lastname: Lawrenson
authors.forename: G
authors.initials: G
authors.lastname: Allt
authors.forename: J A
authors.initials: JA
authors.lastname: Firth
mesh_terms: D000818:Animals; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface / Q000032:analysis*; D030161:Avian Proteins; D051926:Basigin; D015415:Biomarkers / Q000032:analysis; D001798:Blood Proteins; D001812:Blood-Brain Barrier; D002540:Cerebral Cortex / Q000196:embryology / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000196:embryology / Q000378:metabolism*; D051272:Glucose Transporter Type 1; D007150:Immunohistochemistry; D007797:Laminin / Q000032:analysis; D008562:Membrane Glycoproteins / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis*; D008833:Microcirculation; D009004:Monosaccharide Transport Proteins / Q000032:analysis; D010841:Pia Mater / Q000196:embryology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D030161:Avian Proteins; D015415:Biomarkers; D001798:Blood Proteins; C102624:Bsg protein, Gallus gallus; C079432:Bsg protein, rat; D051272:Glucose Transporter Type 1; D007797:Laminin; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; C495679:Slc2a1 protein, rat; C058783:laminin beta2; D051926:Basigin