title: Connexin immunoreactivity in glial cells of the rat retina.
abstract: The rat retina contains two types of macroglial cells, Müller cells, radial glial cells that are the principal macroglial cells of vertebrate retinas, and astrocytes associated with the surface vasculature. In addition to the often-described gap-junctional coupling between astrocytes, coupling also occurs between astrocytes and Müller cells. Immunohistochemistry and confocal microscopy were used to identify connexins in the retinas of pigmented rats. Several antibodies directed against connexin43 stained astrocytes, identified using antibodies directed against glial fibrillary acidic protein (GFAP). In addition, two connexin43 antibodies stained Müller cells, identified with antibodies directed against S100 or glutamine synthetase. Connexin30-immunoreactive puncta were confined to the vitreal surface of the retina and colocalized with GFAP-immunoreactive astrocyte processes. Connexin45 immunoreactivity was associated with both astrocytes and Müller cells. We conclude that retinal glial cells express multiple connexins, and the patterns of immunostaining that we observe in this study are consistent with the expression of connexins30, -43, and possibly -45 by astrocytes and the expression of connexins43 and -45 by Müller cells. As gap-junction channels may be formed by both homotypic and heterotypic hemichannels, and the hemichannels may themselves be homomeric or heteromeric, there exists a multitude of possible gap-junction channels that could underlie the homotypic coupling between retinal astrocytes and the heterotypic coupling between astrocytes and Müller cells.
authors.affiliation: Department of Physiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA. zahsx001@tc.umn.edu
authors.forename: Kathleen R
authors.initials: KR
authors.lastname: Zahs
authors.forename: Paulo
authors.initials: P
authors.lastname: Kofuji
authors.forename: Carola
authors.initials: C
authors.lastname: Meier
authors.forename: Rolf
authors.initials: R
authors.lastname: Dermietzel
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism; D015153:Blotting, Western; D017630:Connexins / Q000096:biosynthesis*; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis; D005974:Glutamate-Ammonia Ligase / Q000096:biosynthesis; D007150:Immunohistochemistry; D008297:Male; D009457:Neuroglia / Q000166:cytology* / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D012160:Retina / Q000166:cytology*; D009418:S100 Proteins / Q000096:biosynthesis
chemical_list: D017630:Connexins; D005904:Glial Fibrillary Acidic Protein; D009418:S100 Proteins; D005974:Glutamate-Ammonia Ligase