Levetiracetam Inhibits Oligomeric A Beta-Induced Glutamate Release From Human Astrocytes

A recently identified mechanism for oligomeric A beta-induced glutamate release from astrocytes involves intracellular Ca2+ elevation, potentially by Ca2+-dependent vesicular release. Evidence suggests that levetiracetam (LEV; Keppra), an antiepileptic drug, can improve cognitive performance in both humans with mild cognitive impairment and animal models of Alzheimer disease. Because LEV acts by modulating neurotransmitter release from neurons by interaction with synaptic vesicles, we tested the effect of LEV on A beta-induced astrocytic release of glutamate. We used a fluorescence resonance energy transfer-based glutamate sensor (termed SuperGluSnFR), whose structure is based on the ligand-binding site of glutamate receptors, to monitor glutamate release from primary cultures of human astrocytes exposed to oligomeric amyloid-beta peptide 1-42 (A beta(42)). We found that LEV (10 mu M) inhibited oligomeric A beta-induced astrocytic glutamate release. In addition, we show that this A beta-induced glutamate release from astrocytes is sensitive to tetanus neurotoxin, an inhibitor of the vesicle release machinery. Taken together, our evidence suggests that LEV inhibits A beta-induced vesicular glutamate release from astrocytes and thus may underlie, at least in part, the ability of LEV to reduce hyperexcitability in Alzheimer disease. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.