The blood-brain barrier of the chick glycogen body (corpus gelatinosum) and its functional implications.
Among recent vertebrates only birds possess a glycogen body (corpus gelatinosum), located in the rhomboidal sinus of the lumbosacral region of the spinal cord and separated from the neural tissue proper. Because of the specific topographical situation of this circumventricular organ, the structure of its vascular system is of special interest with respect to the still unsolved functional problems. The existence of a blood-brain barrier is demonstrated by the exclusion of intravascularly injected tracer (horseradish peroxidase), and immunocytochemical demonstration of glucose transporter-1 as a functional marker and of neurothelin, occludin and ZO-1 as structural markers. Alkaline phosphatase and gamma-glutamyltransferase activities, two enzyme reactions frequently used for demonstration of an established blood-brain barrier in vitro, were localized histochemically on the plasmalemma of glycogen body cells and were absent from the endothelium. In addition, local enlargements of the intercellular space were observed by transmission and scanning electron microscopy. In accordance with the concept of a third circulation the cerebrospinal fluid may be the vehicle for distributing substances originating in the glycogen body to the CNS, while the vascular endothelium maintains the internal milieu by virtue of its dynamic barrier functions.
Möller
Wilhelm
W
Institute of Anatomy and Cell Biology, Justus Liebig University, Aulweg 123, 35385, Giessen, Germany. w.moeller-lahnau@t-online.de
Kummer
Wolfgang
W
D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D030161:Avian Proteins; D051926:Basigin; D001798:Blood Proteins; D001808:Blood Vessels / Q000737:chemistry / Q000166:cytology / Q000648:ultrastructure; D001812:Blood-Brain Barrier / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D015153:Blotting, Western; D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure; D002645:Chickens; D002847:Chromatography, Agarose; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D015870:Gene Expression; D051272:Glucose Transporter Type 1; D006003:Glycogen / Q000502:physiology; D006651:Histocytochemistry; D006735:Horseradish Peroxidase / Q000008:administration & dosage / Q000493:pharmacokinetics; D007150:Immunohistochemistry; D007269:Injections, Intra-Arterial; D008161:Lumbosacral Region / Q000033:anatomy & histology / Q000098:blood supply* / Q000502:physiology; D008562:Membrane Glycoproteins / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D009004:Monosaccharide Transport Proteins / Q000032:analysis / Q000235:genetics; D062793:Occludin; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000098:blood supply* / Q000378:metabolism / Q000648:ultrastructure; D019108:Tight Junctions / Q000737:chemistry / Q000648:ultrastructure; D005723:gamma-Glutamyltransferase / Q000032:analysis
D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D030161:Avian Proteins; D001798:Blood Proteins; C102624:Bsg protein, Gallus gallus; C079432:Bsg protein, rat; D051272:Glucose Transporter Type 1; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D062793:Occludin; C568987:Ocln protein, rat; D051926:Basigin; D006003:Glycogen; D006735:Horseradish Peroxidase; D005723:gamma-Glutamyltransferase; D000469:Alkaline Phosphatase