Cellular and synaptic localization of EAAT2a in human cerebral cortex

Marcello Melone, Michele Bellesi, Alessandro Ducati, Maurizio Iacoangeli, Fiorenzo Conti

Research output: Contribution to journalArticle

Abstract

We used light and electron microscopic immunocytochemical techniques to analyze the distribution, cellular and synaptic localization of EAAT2, the main glutamate transporter, in normal human neocortex. EAAT2a-immunoreactivity (ir) was in all layers and consisted of small neuropilar puncta and rare cells. In white matter EAAT2a+ cells were numerous. Electron microscopic studies showed that in gray matter ∼77% of immunoreactive elements were astrocytic processes, ∼14% axon terminals, ∼2.8% dendrites, whereas ∼5% were unidentifiable. In white matter, ∼81% were astrocytic processes, ∼17% were myelinated axons, and ∼2.0% were unidentified. EAAT2a-ir was never in microglial cells and oligodendrocytes. Pre-embedding electron microscopy showed that ∼67% of EAAT2a expressed at (or in the vicinity of) asymmetric synapses was in astrocytes, ∼17% in axon terminals, while ∼13% was both in astrocytes and in axons. Post-embedding electron microscopy studies showed that in astrocytic processes contacting asymmetric synapses and in axon terminals, gold particle density was ∼25.1 and ∼2.8 particles/μm 2, respectively, and was concentrated in a membrane region extending for ∼300 nm from the active zone edge. Besides representing the first detailed description of EAAT2a in human cerebral cortex, these findings may contribute to understanding its role in the pathophysiology of neuropsychiatric diseases.

Original languageEnglish
Pages (from-to)1-14
Number of pages14
JournalFrontiers in Neuroanatomy
Issue numberJAN
DOIs
Publication statusPublished - Jan 14 2011

Fingerprint

Presynaptic Terminals
Cerebral Cortex
Astrocytes
Synapses
Axons
Electron Microscopy
Electrons
Amino Acid Transport System X-AG
Neocortex
Oligodendroglia
Dendrites
Gold
Light
Membranes
White Matter

Keywords

  • EAAT2
  • Glutamate transporters
  • Human neocortex
  • Immunogold post-embedding electron microscopy

ASJC Scopus subject areas

  • Anatomy
  • Neuroscience (miscellaneous)
  • Cellular and Molecular Neuroscience

Cite this

Cellular and synaptic localization of EAAT2a in human cerebral cortex. / Melone, Marcello; Bellesi, Michele; Ducati, Alessandro; Iacoangeli, Maurizio; Conti, Fiorenzo.

In: Frontiers in Neuroanatomy, No. JAN, 14.01.2011, p. 1-14.

Research output: Contribution to journalArticle

Melone, Marcello ; Bellesi, Michele ; Ducati, Alessandro ; Iacoangeli, Maurizio ; Conti, Fiorenzo. / Cellular and synaptic localization of EAAT2a in human cerebral cortex. In: Frontiers in Neuroanatomy. 2011 ; No. JAN. pp. 1-14.
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