NMDA-receptors 1 and 2A/B coassembly increased in human epileptic focal cortical dysplasia

Purpose: This study was designed to quantify the relation between expressio ns of NMDA receptor (NMDAR) subunits (1 and 2A/B) and the epileptogenicity in human focal cortical dysplasia. Methods: Immunoblotting and immunoprecipitation were used to quantify these receptor subunits in tissue resected from EEG-verified epileptic and dista l nonepileptic frontal cortical areas in each of three patients as determin ed by chronic subdural electrode recordings. In each patient, adjacent sect ions were immunostained to verify that the numbers of dysplastic neurons we re greater in epileptic than in nonepileptic cortex. Results: In all patients, NMDAR2A/B expressions and their coassemblies with NMDAR1 were increased in epileptic dysplastic cortex compared with the rel atively normal appearing nonepileptic cortex. For all three patients, there were no significant differences in NMDAR1 protein expressions between the two EEG groups. Conclusions: These results suggest that increased NMDAR1-NMDAR2A/B coassemb ly contributes to hyperexcitability in dysplastic cortical neurons and foca l seizure onsets.