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Updated: Aug 7, 2026

Deriving the Time Course of Glutamate Clearance with a Deconvolution Analysis of Astrocytic Transporter Currents
Published on: August 7, 2013
Pyroglutamate stimulates Na+ -dependent glutamate transport across the blood-brain barrier
Richard A Hawkins1, Ian A Simpson, Ashwini Mokashi
1Department of Physiology and Biophysics, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064-3095, USA. rah@post.harvard.edu
Abstract:
Regulation of Na(+)-dependent glutamate transport was studied in isolated luminal and abluminal plasma membranes derived from the bovine blood-brain barrier. Abluminal membranes have Na(+)-dependent glutamate transporters while luminal membranes have facilitative transporters. This organization allows glutamate to be actively removed from brain. gamma-Glutamyl transpeptidase, the first enzyme of the gamma-glutamyl cycle (GGC), is on the luminal membrane. Pyroglutamate (oxoproline), an intracellular product of GGC, stimulated Na(+)-dependent transport of glutamate by 46%, whereas facilitative glutamate uptake in luminal membranes was inhibited. This relationship between GGC and glutamate transporters may be part of a regulatory mechanism that accelerates glutamate removal from brain.
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