title: Glycogen phosphorylase isozyme pattern in mammalian retinal Müller (glial) cells and in astrocytes of retina and optic nerve.
abstract: Müller cells, the radially oriented dominant macroglial cells of the retina, are known to contain abundant glycogen as well as the key enzyme for its degradation, glycogen phosphorylase (GP), but the expressed isozyme pattern is unknown. To elucidate the isoform expression pattern, specific antisera directed against the brain (BB) and muscle (MM) isoforms of GP were applied to retinal sections, isolated Müller cells, and sections of the optic nerve. We show that Müller cells of rat, rabbit, guinea pig, and mouse retina exclusively express the BB isoform. Astrocytes of rat and rabbit optic nerve, as well as retina express only the BB isoform. In contrast, astrocytes in the brain and spinal cord as well as the epithelial cells of the pars caeca and of the ciliary body express both the BB and MM isoform. This result may indicate some differences in the role of glycogen in retinal macroglia and brain astrocytes, reflecting a local specialization of macroglia in the retina proper.
authors.affiliation: Physiologisch-Chemisches Institut der Universität, Tübingen, Germany.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Pfeiffer-Guglielmi
authors.forename: Mike
authors.initials: M
authors.lastname: Francke
authors.forename: Andreas
authors.initials: A
authors.lastname: Reichenbach
authors.forename: Burkhard
authors.initials: B
authors.lastname: Fleckenstein
authors.forename: Günther
authors.initials: G
authors.lastname: Jung
authors.forename: Bernd
authors.initials: B
authors.lastname: Hamprecht
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000201:enzymology*; D001921:Brain / Q000166:cytology / Q000201:enzymology; D002924:Ciliary Body / Q000166:cytology / Q000201:enzymology; D004847:Epithelial Cells / Q000166:cytology / Q000201:enzymology; D006003:Glycogen / Q000378:metabolism; D024981:Glycogen Phosphorylase / Q000378:metabolism*; D025002:Glycogen Phosphorylase, Brain Form / Q000378:metabolism; D024982:Glycogen Phosphorylase, Muscle Form / Q000378:metabolism; D006168:Guinea Pigs; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism; D051379:Mice; D009457:Neuroglia / Q000166:cytology / Q000201:enzymology*; D009900:Optic Nerve / Q000166:cytology / Q000201:enzymology*; D011817:Rabbits; D051381:Rats; D011914:Rats, Inbred BN; D012160:Retina / Q000166:cytology / Q000201:enzymology*; D013116:Spinal Cord / Q000166:cytology / Q000201:enzymology
chemical_list: D007527:Isoenzymes; D006003:Glycogen; D024981:Glycogen Phosphorylase; D025002:Glycogen Phosphorylase, Brain Form; D024982:Glycogen Phosphorylase, Muscle Form