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

Fiorenzo Conti, Laura Vitellaro Zuccarello, Paolo Barbaresi, Andrea Minelli, Nicholas C. Brecha, Marcello Melone

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish
Pages (from-to)482-494
Number of pages13
JournalJournal of Comparative Neurology
Volume409
Issue number3
DOIs
Publication statusPublished - Jul 5 1999

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Keywords

  • Astrocytes
  • Confocal microscopy
  • Inhibitory transmission
  • Leptomeninges
  • Neocortex
  • Synapses

ASJC Scopus subject areas

  • Neuroscience(all)

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