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Differentiation of a unique macroglial cell type in the pecten oculi of the chicken
Author(s) -
Gerhardt Holger,
Schuck Jochen,
Wolburg Hartwig
Publication year - 1999
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/(sici)1098-1136(199912)28:3<201::aid-glia4>3.0.co;2-m
Subject(s) - biology , retina , glial fibrillary acidic protein , microbiology and biotechnology , neuroglia , optic nerve , retinal , astrocyte , muller glia , glutamine synthetase , cell type , immunocytochemistry , anatomy , neuroscience , central nervous system , stem cell , immunology , cell , immunohistochemistry , progenitor cell , biochemistry , endocrinology , glutamine , amino acid
Glial cells in the CNS of vertebrates serve specialized functions in close interaction with surrounding neurons and blood vessels. In the avian eye, the neural tissue (retina) and the supporting vascular structure (pecten oculi) are spatially separated and comprise distinct glial cell types, i.e., the Müller glia and the pecteneal glia, respectively. In the present study we combined morphological and immunocytochemical investigations on the differentiation of the pecteneal glia in comparison to the retinal Müller glia, the retinal pigment epithelium, and the astrocytic cells of the optic nerve head in order to elucidate the nature, origin, and function of the pecteneal glia. Conventional transmission electron microscopy and freeze‐fracture imaging revealed striking similarities between the pecteneal glia and retinal pigment epithelial cells at the transition zone to the optic nerve head. Immunofluorescence investigation identified specific labeling for vimentin and glutamine synthetase (GS) but not for glial fibrillary acidic protein (GFAP) in the mature pecteneal glia. Immunogold labeling confirmed the cellular specificity. GS labeling was weak during embryonic development but increasingly strong after hatching. Surprisingly, the intraneuroectodermal endothelial cells were highly immunopositive for GS throughout embryonic development and lost GS expression after hatching. GS expression in the pecteneal glia may participate in pH‐regulation of the avian eye. Endothelial GS expression in the developing CNS may detoxify detrimental ammonium concentrations resulting from egg yolk degradation. GLIA 28:201–214, 1999. © 1999 Wiley‐Liss, Inc.