Arachidonic acid activates a proton current in the rat glutamate transporter EAAT4

Anastassios V. Tzingounis, Chien Liang Lin, Jeffrey D. Rothstein, Michael P. Kavanaugh

Research output: Contribution to journalArticlepeer-review

Abstract

The excitatory amino acid transporter EAAT4 is expressed predominantly in Purkinje neurons in the rat cerebellum (1-3), and it participates in postsynaptic re-uptake of glutamate released at the climbing fiber synapse (4). Transporter-mediated currents in Purkinje neurons are increased more than 3-fold by arachidonic acid, a second messenger that is liberated following depolarization-induced Ca2+ activation of phospholipase A2 (5). In this study we demonstrate that application of arachidonic acid to oocytes expressing rat EAAT4 increased glutamate-induced currents to a similar extent. However, arachidonic acid did not cause an increase in the rate of glutamate transport or in the chloride current associated with glutamate transport but rather activated a proton-selective conductance. These data reveal a novel action of arachidonate on a glutamate transporter and suggest a mechanism by which synaptic activity may decrease intracellular pH in neurons where this transporter is localized.

Original languageEnglish
Pages (from-to)17315-17317
Number of pages3
JournalJournal of Biological Chemistry
Volume273
Issue number28
DOIs
StatePublished - Jul 10 1998

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