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Full-Text Articles in Medicine and Health Sciences
Glutamine Uptake By Neurons: Interaction Of Protons With System A Transporters, Farrukh A. Chaudhry, Dietmar Schmitz, Richard J. Reimer, Peter Larsson, Andrew T. Gray, Roger Nicoll, Michael Kavanaugh, Robert H. Edwards
Glutamine Uptake By Neurons: Interaction Of Protons With System A Transporters, Farrukh A. Chaudhry, Dietmar Schmitz, Richard J. Reimer, Peter Larsson, Andrew T. Gray, Roger Nicoll, Michael Kavanaugh, Robert H. Edwards
Biomedical and Pharmaceutical Sciences Faculty Publications
Astrocytes provide the glutamine required by neurons to synthesize glutamate and GABA. However, the mechanisms involved in glutamine transfer from glia to neurons have remained poorly understood. Recent work has implicated the System N transporter SN1 in the efflux of glutamine from astrocytes and the very closely related System A transporters SA1 and SA2 in glutamine uptake by neurons. To understand how these closely related proteins mediate flux in different directions, we have examined their ionic coupling. In contrast to the electroneutral exchange of H+ for Na+ and neutral amino acid catalyzed by SN1, we now show that …
Dynamic Equilibrium Between Coupled And Uncoupled Modes Of A Neuronal Glutamate Transporter, Lars Borre, Michael Kavanaugh, Baruch I. Kanner
Dynamic Equilibrium Between Coupled And Uncoupled Modes Of A Neuronal Glutamate Transporter, Lars Borre, Michael Kavanaugh, Baruch I. Kanner
Biomedical and Pharmaceutical Sciences Faculty Publications
In the brain, the neurotransmitter glutamate is removed from the synaptic cleft by (Na+ + K+)-coupled transporters by an electrogenic process. Moreover, these transporters mediate a sodium- and glutamate-dependent uncoupled chloride conductance. In contrast to the wild type, the uptake of radiolabeled substrate by the I421C mutant is inhibited by the membrane-impermeant [2-(trimethylammonium)ethyl]methanethiosulfonate and also by other sulfhydryl reagents. In the wild-type and the unmodified mutant, substrate-induced currents are inwardly rectifying and reflect the sum of the coupled electrogenic flux and the anion conductance. Remarkably, the I421C mutant modified by sulfhydryl reagents exhibits currents that are non-rectifying …