title: Protein components of the blood-brain barrier (BBB) in the mediobasal hypothalamus.
abstract: The blood-brain barrier (BBB) plays an important role in controlling the access of substances to the brain. Of the circumventricular organs (CVO), i.e. areas that lack a BBB, the median eminence and its close relationship with the hypothalamic arcuate nucleus plays an important role in controlling the entry of blood-borne substances to neurons of the mediobasal hypothalamus. In order to clarify the nature of the BBB in the median eminence-arcuate nucleus complex, we have used immunohistochemistry and antisera to protein components of the BBB-(1) tight junctions, claudin-5 and zona occludens-1 (ZO-1); (2) endothelial cells: (a) all endothelial cells: rat endothelial cell antigen-1 (RECA-1), (b) endothelial cells at BBB: endothelial barrier antigen (EBA), glucose transporter 1 (GLUT1) and transferrin receptor (TfR), and (c) endothelial cells at CVOs: dysferlin; (3) basal lamina: laminin; (4) vascular smooth muscle cells: smooth muscle actin (SMA); (5) pericytes: chondroitin sulfate proteoglycan (NG2); (6) glial cells: (a) astrocytes: glial fibrillary acidic protein (GFAP), (b) tanycytes: dopamine- and cAMP-regulated phosphoprotein of 32kDA (DARPP-32), (c) microglia: CD11b. Neuronal cell bodies located in the ventromedial aspect of the arcuate nucleus were visualized by antiserum to agouti-related protein (AgRP). The study provides a detailed analysis on the cellular localization of BBB components in the mediobasal hypothalamus. Some vessels in the ventromedial aspect of the arcuate nucleus lacked the BBB markers EBA and TfR, suggesting an absence of an intact BBB. These vessels may represent a route of entry for circulating substances to a subpopulation of arcuate nucleus neurons.
authors.affiliation: Department of Neuroscience, The Retzius Laboratory, Karolinska Institutet, Retzius väg 8, SE-171 77 Stockholm, Sweden.
authors.forename: Ebba
authors.initials: E
authors.lastname: Norsted
authors.forename: Burçak
authors.initials: B
authors.lastname: Gömüç
authors.forename: Björn
authors.initials: B
authors.lastname: Meister
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000098:blood supply / Q000378:metabolism / Q000648:ultrastructure; D015415:Biomarkers / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000378:metabolism* / Q000648:ultrastructure; D062507:Claudin-5; D042783:Endothelial Cells / Q000378:metabolism* / Q000648:ultrastructure; D007031:Hypothalamus / Q000098:blood supply* / Q000378:metabolism* / Q000648:ultrastructure; D007150:Immunohistochemistry; D008297:Male; D008473:Median Eminence / Q000098:blood supply / Q000378:metabolism / Q000648:ultrastructure; D008565:Membrane Proteins / Q000378:metabolism; D008833:Microcirculation / Q000378:metabolism* / Q000648:ultrastructure; D032389:Myocytes, Smooth Muscle / Q000378:metabolism / Q000648:ultrastructure; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009457:Neuroglia / Q000378:metabolism / Q000648:ultrastructure; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure; D020286:Pericytes / Q000378:metabolism / Q000648:ultrastructure; D010750:Phosphoproteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D019108:Tight Junctions / Q000378:metabolism* / Q000648:ultrastructure; D062826:Zonula Occludens-1 Protein
chemical_list: D015415:Biomarkers; D062507:Claudin-5; C491510:Cldn5 protein, rat; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein