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Neurochemical Research

, Volume 43, Issue 1, pp 59–65 | Cite as

Inhibition of Gap Junction Elevates Glutamate Uptake in Cultured Astrocytes

  • Katsura TakanoEmail author
  • Masato Ogawa
  • Kenji Kawabe
  • Mitsuaki Moriyama
  • Yoichi Nakamura
Original Paper

Abstract

Glutamate uptake is a main function of astrocytes to keep extracellular glutamate levels low and protect neurons against glutamate-induced excitotoxicity. On the other hand, astrocyte networks formed by gap junctions, which are consisted with connexins and connecting neighboring cells, are reported to play a critical role in maintaining the homeostasis in the brain. In the present study, we examined the effects of gap junction inhibitors on the glutamate uptake activity in cultured rat cortical astrocytes. At first, we confirmed the effects of gap junction inhibitors, 1-octanol and carbenoxolone, on cell–cell communication by the scrape-loading assay using a fluorescent dye Lucifer yellow. Both of 1-octanol and carbenoxolone treatments for 20 min in cultured astrocytes significantly suppressed the cell–cell communication assessed as the distance of dye-spreading. 1-octanol and carbenoxolone increased the glutamate uptake by astrocytes and glutamate aspartate transporter (GLAST) expression on the cell membrane. These results suggest that gap junction inhibitors increase the glutamate uptake activity through the increase of GLAST proteins located on the cell membrane. The regulation of gap junction in astrocytes might protect neurons against glutamate-induced excitotoxicity.

Keywords

Astrocyte Gap junction Carbenoxolone 1-Octanol Glutamate uptake 

Abbreviations

CNS

Central nervous system

Cx

Connexin

DMEM

Dulbecco’s modified eagle medium

FBS

Fetal bovine serum

HHBSS

HEPES-buffered Hank’s balanced salt solution

HKR

HEPES-buffered Krebs Ringer solution

HRP

Horseradish peroxidase

PBS

Phosphate-buffered saline

Notes

Acknowledgements

This work was supported in part by JSPS KAKENHI Grant Number JP26850209 to K.T., JP26450447 to M.M., JP24621008 to Y.N., and JP15K07768 to Y.N.

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Copyright information

© Springer Science+Business Media New York 2017

Authors and Affiliations

  • Katsura Takano
    • 1
    Email author
  • Masato Ogawa
    • 1
  • Kenji Kawabe
    • 1
  • Mitsuaki Moriyama
    • 1
  • Yoichi Nakamura
    • 1
  1. 1.Laboratory of Integrative Physiology in Veterinary SciencesOsaka Prefecture UniversityIzumisanoJapan

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