Laminar and subcellular heterogeneity of GLAST and GLT-1 immunoreactivity in the developing postnatal mouse hippocampus

ABSTRACT Astrocytes express two sodium‐coupled transporters, glutamate–aspartate transporter (GLAST) and glutamate transporter‐1 (GLT‐1), which are essential for the maintenance of low extracellular glutamate levels. We performed a comparative analysis of the laminar and subcellular expression profi...

Full description

Saved in:
Bibliographic Details
Published in:Journal of comparative neurology (1911) 2014-01, Vol.522 (1), p.204-224
Main Authors: Schreiner, Alexandra E., Durry, Simone, Aida, Tomomi, Stock, Martin C., Rüther, Ulrich, Tanaka, Kohichi, Rose, Christine R., Kafitz, Karl W.
Format: Article
Language:English
Subjects:
Animals
astrocyte
Astrocytes - metabolism
Blotting, Western
EAAT
Excitatory Amino Acid Transporter 1 - metabolism
Excitatory Amino Acid Transporter 2 - metabolism
Female
GFAP
GFAP, S100β
Glial Fibrillary Acidic Protein
Hippocampus - growth & development
Hippocampus - metabolism
Immunohistochemistry
Male
Mice
Mice, Inbred BALB C
Microscopy, Confocal
Microscopy, Fluorescence
Nerve Tissue Proteins - metabolism
perivascular endfeet
S100β
Subcellular Fractions - metabolism
Up-Regulation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:ABSTRACT Astrocytes express two sodium‐coupled transporters, glutamate–aspartate transporter (GLAST) and glutamate transporter‐1 (GLT‐1), which are essential for the maintenance of low extracellular glutamate levels. We performed a comparative analysis of the laminar and subcellular expression profile of GLAST and GLT‐1 in the developing postnatal mouse hippocampus by using immunohistochemistry and western blotting and employing high‐resolution fluorescence microscopy. Astrocytes were identified by costaining with glial fibrillary acidic protein (GFAP) or S100β. In CA1, the density of GFAP‐positive cells and GFAP expression rose during the first 2 weeks after birth, paralleled by a steady increase in GLAST immunoreactivity and protein content. Upregulation of GLT‐1 was completed only at postnatal days (P) P20–25 and was thus delayed by about 10 days. GLAST staining was highest along the stratum pyramidale and was especially prominent in astrocytes at P3–5. GLAST immunoreactivity indicated no preferential localization to a specific cellular compartment. GLT‐1 exhibited a laminar expression pattern from P10–15 on, with the highest immunoreactivity in the stratum lacunosum‐moleculare. At the cellular level, GLT‐1 immunoreactivity did not entirely cover astrocyte somata and exhibited clusters at processes. In neonatal and juvenile animals, discrete clusters of GLT‐1 were also detected at perivascular endfeet. From these results, we conclude there is a remarkable subcellular heterogeneity of GLAST and GLT‐1 expression in the developing hippocampus. The clustering of GLT‐1 at astrocyte endfeet indicates that it might serve a specialized functional role at the blood–brain barrier during formation of the hippocampal network. J. Comp. Neurol. 522:204–224, 2014. © 2013 Wiley Periodicals, Inc. Glutamate transporters are essential for the maintenance of low extracellular glutamate levels. Our study using immunohistochemistry, western blotting, and high‐resolution fluorescence microscopy provides evidence for subcellular heterogeneity of GLAST and GLT‐1 expression in the developing hippocampus, which might serve a specialized functional role during formation of the hippocampal network.
ISSN:0021-9967
1096-9861
DOI:10.1002/cne.23450