Investigation of glutamine and GABA levels in patients with idiopathic generalized epilepsy using MEGAPRESS

Abstract

Purpose Idiopathic generalized epilepsies (IGE) comprise a group of clinical syndromes associated with spike wave discharges, putatively linked to alterations in neurotransmission. The purpose of this study was to investigate whether patients with IGE have altered glutamine and γ-aminobutyric acid (GABA) levels indicative of altered excitatory and inhibitory neurotransmission in frontal regions. Materials and Methods Single-voxel MEGA-edited PRESS magnetic resonance imaging (MRI) spectra were acquired from a 30-mL voxel in the dorsolateral prefrontal cortex in 13 patients with IGE (8 female) and 16 controls (9 female) at 3T. Metabolite concentrations were derived using LCModel. Differences between groups were investigated using an unpaired t-test. Results Patients with IGE were found to have significantly higher glutamine than controls (P = 0.02). GABA levels were also elevated in patients with IGE (P = 0.03). Conclusion Patients with IGE have increased frontal glutamine and GABA compared with controls. Since glutamine has been suggested to act as a surrogate for metabolically active glutamate, it may represent a marker for excitatory neurotransmission.

GABA and glutamate levels in occlusal splint-wearing males with possible bruxism

“…A recent case report documented a 5-year old male with a cystic lesion compressing the left hippocampus and exhibiting teeth grinding behavior during sleep (77). It has been found that DLPFC of idiopathic generalized epilepsy patients demonstrate increased levels of glutamine and GABA compared with controls (57). This differs from our study in that DLPFC of OCS subjects showed significantly lower levels of GABA+ and higher levels of Glu (see Table 1).…”

“…Both single voxel short echo time Point RESolved Spectroscopy (PRESS) spectra (TE=30 ms, TR=1500 ms, 128 averages) and GABA-edited spectra (TR=1500 ms, TE=68 ms) using MEGA-PRESS (55-57) were obtained from four volumes of interest (VOIs): thalamus (25×25×25 mm 3 , 392 averages), hippocampus (17×40×17 mm 3 , 512 averages), DLPFC (25×30×22 mm 3 , 392 averages) and dACC/preSMA (25×35×25 mm 3 , 392 averages). A reference spectrum without water suppression was obtained in each brain region for phase and frequency correction.…”

Temporal Dynamics of Antidepressant Ketamine Effects on Glutamine Cycling Follow Regional Fingerprints of AMPA and NMDA Receptor Densities

“…Glutamine levels have been suggested as a marker for synaptically active glutamate and excitatory neurotransmission (Chowdhury et al, 2015;Hancu and Port, 2011). Changes in glutamine levels may be a particularly sensitive measure for detecting acute downstream effects following ketamine administration.…”

Sleep Spindles Are Related to Schizotypal Personality Traits and Thalamic Glutamine/Glutamate in Healthy Subjects

“…Owing to the tight spectral overlap between Glu and Gln at 3 T, 39,41 the sum of both, Glx, was used to investigate the link between Glu levels, spindle rhythms, and schizotypy. The concentrations were corrected for partial volume contamination of CSF, 42 using the correction factor given in Chowdhury et al 43 To control for differences in the fractions of GM and WM within the voxel we covaried in an additional analysis for the GM/WM fraction 43,44 in a partial correlation design.…”