Abstract #1953

GABA Measured by 1H-MRS Is Not Affected by Tiagabine.

C. John Evans¹, Jim F. M. Myers², Nicola Kalk², Richard Anthony Edward Edden³, Anne Lingford-Hughes⁴

¹CUBRIC, School of Psychology, Cardiff University, Cardiff, Wales, United Kingdom; ²Psychopharmacology Unit,, University of Bristol, Bristol, United Kingdom; ³Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; ⁴Neuropsychopharmacology Unit, Imperial College London, London, United Kingdom

Tiagabine, an antiepileptic drug, acts by blocking the reuptake of inhibitory neurotransmitter GABA from the synapse, thus increasing GABA concentration at the synaptic cleft. We performed J-difference edited ¹H-MRS before and after tiagabine administration to investigate whether MRS was sensitive to changes in extracellular GABA concentration. Ten participants were studied, and MRS data were acquired from occipital and limbic voxels. No significant change was detected in GABA, thus indicating that although tiagabine has GABAergic action, it does not affect the total GABA concentration.