Neuronal and glial glutamate transporters possess an SH-based redox regulatory mechanism

Davide Trotti, Barbara Lodi Rizzini, Daniela Rossi, Oyvind Haugeto, Giorgio Racagni, Niels C. Danbolt, Andrea Volterra

Research output: Contribution to journalArticle

Abstract

Glutamate uptake into nerve cells and astrocytes via high-affinity transporters controls the extracellular glutamate concentration in the brain, with major implications for physiological excitatory neurotransmission and the prevention of excitotoxicity. We report here that three recently cloned rat glutamate transporter subtypes, viz. EAAC1 (neuronal), GLT1 and GLAST (glial), possess a redox-sensing property, undergoing opposite functional changes in response to oxidation or reduction of reactive sulphydryls present in their structure. In particular, thiol oxidation with 5,5'-dithio-bis(2-nitrobenzoic) acid (DTNB) and disulphide reduction with dithiothreitol (DTT) result, respectively, in reduced and increased uptake capacity by a preparation of partially purified brain transporters as well as by the three recombinant proteins reconstituted into liposomes. In this model system, EAAC1, GLT1 and GLAST react similarly to DTT/DTNB exposures despite their different contents of cysteines, suggesting that only the conserved residues might be involved in redox modulation. Redox sensitivity is a property of the glutamate transporters also when present in their native cell environment. Thus, by using cultured cortical astrocytes and the whole-cell patch-clamp technique we were able to observe dynamic increase and decrease of the glutamate uptake current in response to application of DTT and DTNB in sequence. Moreover, in the same paradigm, DDT-reversible current inhibition was observed with hydrogen peroxide instead of DTNB, indicating that the SH-based redox modulatory site is targeted by endogenous oxidants and might constitute an important physiological or pathophysiological regulatory mechanism of glutamate uptake in vivo.

Original languageEnglish
Pages (from-to)1236-1243
Number of pages8
JournalEuropean Journal of Neuroscience
Volume9
Issue number6
DOIs
Publication statusPublished - 1997

Fingerprint

Dithionitrobenzoic Acid
Amino Acid Transport System X-AG
Neuroglia
Oxidation-Reduction
Glutamic Acid
Dithiothreitol
Astrocytes
Nitrobenzoates
DDT
Brain
Patch-Clamp Techniques
Recombinant Proteins
Sulfhydryl Compounds
Oxidants
Liposomes
Synaptic Transmission
Disulfides
Hydrogen Peroxide
Cysteine
Neurons

Keywords

  • Endogenous oxidants and reductants
  • Excitatory neurotransmission
  • Excitotoxicity
  • GLT1 and GLAST transporters
  • Oxidative stress
  • Rat EAAC1

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Neuronal and glial glutamate transporters possess an SH-based redox regulatory mechanism. / Trotti, Davide; Rizzini, Barbara Lodi; Rossi, Daniela; Haugeto, Oyvind; Racagni, Giorgio; Danbolt, Niels C.; Volterra, Andrea.

In: European Journal of Neuroscience, Vol. 9, No. 6, 1997, p. 1236-1243.

Research output: Contribution to journalArticle

Trotti, Davide ; Rizzini, Barbara Lodi ; Rossi, Daniela ; Haugeto, Oyvind ; Racagni, Giorgio ; Danbolt, Niels C. ; Volterra, Andrea. / Neuronal and glial glutamate transporters possess an SH-based redox regulatory mechanism. In: European Journal of Neuroscience. 1997 ; Vol. 9, No. 6. pp. 1236-1243.
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