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Updated: Aug 15, 2026

Deriving the Time Course of Glutamate Clearance with a Deconvolution Analysis of Astrocytic Transporter Currents
Published on: August 7, 2013
Ion fluxes associated with excitatory amino acid transport
J I Wadiche1, S G Amara, M P Kavanaugh
1Vollum Institute, Oregon Health Sciences University, Portland 97201, USA.
Abstract:
Flux of substrate and charge mediated by three cloned excitatory amino acid transporters widely expressed in human brain were studied in voltage-clamped Xenopus oocytes. Superfusion of L-glutamate or D-aspartate resulted in currents due in part to electrogenic Na+ cotransport, which contributed 1 net positive charge per transport cycle. A significant additional component of the currents was due to activation of a reversible anion flux that was not thermodynamically coupled to amino acid transport. The selectivity sequence of this ligand-activated conductance was NO3- > 1- > Br- > Cl- > F-. The results suggest that these proteins mediate both transporter- and channel-like modes of permeation, providing a potential mechanism for dampening cell excitability, in addition to removal of transmitter.
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