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Neuronal, glial, and epithelial localization of γ‐aminobutyric acid transporter 2, a high‐affinity γ‐aminobutyric acid plasma membrane transporter, in the cerebral cortex and neighboring structures
Author(s) -
Conti Fiorenzo,
Zuccarello Laura Vitellaro,
Barbaresi Paolo,
Minelli Andrea,
Brecha Nicholas C.,
Melone Marcello
Publication year - 1999
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19990705)409:3<482::aid-cne11>3.0.co;2-o
Subject(s) - choroid plexus , biology , immunocytochemistry , ependyma , microbiology and biotechnology , ependymal cell , glial fibrillary acidic protein , gaba transporter , cerebral cortex , neocortex , neuroscience , astrocyte , neuropil , axon , central nervous system , immunohistochemistry , neurotransmitter , immunology , endocrinology
Neuronal and glial high‐affinity Na + /Cl − ‐dependent plasma membrane γ‐aminobutyric acid (GABA) transporters (GATs) contribute to regulating neuronal function. We investigated in the cerebral cortex and neighboring regions of adult rats the distribution and cellular localization of the GABA transporter GAT‐2 by immunocytochemistry with affinity‐purified polyclonal antibodies that react monospecifically with a protein of 82 kDa. Conventional and confocal laser‐scanning light microscopic studies revealed intense GAT‐2 immunoreactivity (ir) in the leptomeninges, choroid plexus, and ependyma. Weak GAT‐2 immunoreactivity also was observed in the cortical parenchyma, where it was localized to puncta of different sizes scattered throughout the radial extension of the neocortex and to few cell bodies. In sections double‐labeled with GAT‐2 and glial fibrillary acidic protein (GFAP) antibodies, some GAT‐2‐positive profiles also were GFAP positive. Ultrastructural studies showed GAT‐2 immunoreactivity mostly in patches of varying sizes scattered in the cytoplasm of neuronal and nonneuronal elements: GAT‐2‐positive neuronal elements included perikarya, dendrites, and axon terminals forming both symmetric and asymmetric synapses; nonneuronal elements expressing GAT‐2 were cells forming the pia and arachnoid mater; astrocytic processes, including glia limitans and perivascular end feet; ependymal cells; and epithelial cells of the choroid plexuses. The widespread cellular expression of GAT‐2 suggests that it may have several functional roles in the overall regulation of GABA levels in the brain. J. Comp. Neurol. 409:482–494, 1999. © 1999 Wiley‐Liss, Inc.