Glutamate clearance mechanisms in resected cortical dysplasia

Object Changes in the expression of glutamate transporters (GLTs) may play a role in the expression of epileptogenicity. Previous studies have shown an increased number of neuronal GLTs in human dysplastic neurons. The expression of glial and neuronal GLTs and glutamine synthetase (GS) in balloon cells (BCs) and BC-containing cortical dysplasia has not been studied. Methods The authors analyzed neocortical samples that were resected in 5 patients who had cortical dysplasia–induced medically intractable focal epilepsy and who underwent extraoperative prolonged electrocorticographic (ECoG) recordings. The expressions of glial (GLT1/EAAT2) and neuronal (EAAT3, EAAC1) GLTs and GS proteins were immunohistochemically studied in all 5 resected samples. The authors also assessed in situ colocalization of GLTs and GS with neuronal and glial markers. Results Balloon cell–containing cortical dysplasia lesions did not exhibit ictal patterns on prolonged extraoperative ECoG recordings. There was a differential express...