Hypothesis & Theory ARTICLE

Front. Syst. Neurosci., 24 November 2011 | http://dx.doi.org/10.3389/fnsys.2011.00094

Extracellular glutamate: functional compartments operate in different concentration ranges

Khaled Moussawi1, Arthur Riegel1, Satish Nair2 and Peter W. Kalivas1*
  • 1 Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA
  • 2 Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO, USA

Extracellular glutamate of glial origin modulates glial and neuronal glutamate release and synaptic plasticity. Estimates of the tonic basal concentration of extracellular glutamate range over three orders of magnitude (0.02–20 μM) depending on the technology employed to make the measurement. Based upon binding constants for glutamate receptors and transporters, this range of concentrations translates into distinct physiological and pathophysiological roles for extracellular glutamate. Here we speculate that the difference in glutamate measurements can be explained if there is patterned membrane surface expression of glutamate release and transporter sites creating extracellular subcompartments that vary in glutamate concentration and are preferentially sampled by different technologies.

Keywords: glutamate, synapse, glia, glutamate uptake, cystine–glutamate exchange, mGluR

Citation: Moussawi K, Riegel A, Nair S and Kalivas PW (2011) Extracellular glutamate: functional compartments operate in different concentration ranges. Front. Syst. Neurosci. 5:94. doi: 10.3389/fnsys.2011.00094

Received: 02 April 2011; Accepted: 31 October 2011;
Published online: 24 November 2011.

Edited by:

Raphael Pinaud, University of Oklahoma Health Sciences Center, USA

Reviewed by:

Stephen Rayport, Columbia University, USA
Jose Bargas, Universidad Nacional Autónoma de México, Mexico

Copyright: © 2011 Moussawi, Riegel, Nair and Kalivas. This is an open-access article subject to a non-exclusive license between the authors and Frontiers Media SA, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and other Frontiers conditions are complied with.

*Correspondence: Peter W. Kalivas, Medical Unversity of South Carolina, 173 Ashley Avenue, DD205, Charleston, SC 29425, USA. e-mail: kalivasp@musc.edu