title: Cell membrane polarity of the epithelial cells in the endolymphatic sac of the guinea pig.
abstract: The epithelial cells of the endolymphatic sac (ES) were studied in order to characterize their glycocalyx composition. Colloidal thorium and cationized ferritin were used as electron-dense markers to visualize the glycocalyx as well as the basement membrane. In addition, enzymatic digestions were performed to identify the reactive components of the glycocalyx responsible for colloidal thorium labeling. The results indicate that the glycocalyx of the ES epithelial lining is very rich in sialic acid. Furthermore, a marked polarity in glycocalyx reactivity is present between the apical and basolateral membranes, whereas difference in glycocalyx reactivity between the light and the dark cells are not obvious. We speculate that the specific composition and the apparent polarity of the ES epithelial cell glycocalyx are of importance to the equilibrium of electrolytes in the ES lumen.
authors: Department of Otorhinolaryngology, University Hospital Utrecht, The Netherlands.
authors: P P
authors: PP
authors: van Benthem
authors: F W
authors: FW
authors: Albers
authors: J C
authors: JC
authors: de Groot
authors: J E
authors: JE
authors: Veldman
authors: E H
authors: EH
authors: Huizing
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D002923:Cilia / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D003051:Cochlea / Q000737:chemistry / Q000201:enzymology / Q000648:ultrastructure; D004712:Endolymphatic Sac / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology / Q000648:ultrastructure; D005260:Female; D005293:Ferritins / Q000494:pharmacology; D006023:Glycoproteins / Q000032:analysis; D006168:Guinea Pigs; D006821:Hyaluronoglucosaminidase / Q000378:metabolism; D009439:Neuraminidase / Q000378:metabolism; D011134:Polysaccharides / Q000032:analysis; D013910:Thorium / Q000494:pharmacology
chemical_list: D006023:Glycoproteins; D011134:Polysaccharides; D013910:Thorium; D005293:Ferritins; D009439:Neuraminidase; D006821:Hyaluronoglucosaminidase