International Journal of Epilepsy 2016; 03(01): 42-62
DOI: 10.1016/j.ijep.2015.12.031
Abstracts
Thieme Medical and Scientific Publishers Private Ltd. 2017

Endogenous activity of NMDA receptors contributes to the enhanced glutamatergic tone and hyperexcitability in resected brain samples obtained for patients with mesial temporal lobe epilepsy

Jyotirmoy Banerjee
1   Center for Excellence in Epilepsy, A Joint NBRC-AIIMS Collaboration, NBRC, Manesar, India
,
Aparna Banerjee Dixit
1   Center for Excellence in Epilepsy, A Joint NBRC-AIIMS Collaboration, NBRC, Manesar, India
,
Manjari Tripathi
3   Department of Neurology, AIIMS, New Delhi, India
,
P Sarat Chandra
2   Department of Neurosurgery, AIIMS, New Delhi, India
› Author Affiliations

Subject Editor:
Further Information

Publication History

Publication Date:
12 May 2018 (online)

Altered excitatory synaptic transmission is one of the primary causes of seizure generation in patients with mesial temporal lobe epilepsy (MTLE). The present study is designed to delineate the contribution of glutamatergic tone under resting conditions to the hyper excitability in patients with MTLE. Resected hippocampal tissues were obtained from patients with MTLE. In these samples spontaneous excitatory postsynaptic currents (EPSCs), sensitive to NMDA receptor antagonist APV (50 [H9262]M) and AMPA receptor antagonist CNQX (10 [H9262]M) were recorded from pyramidal neurons at −70 mV. We observed that frequency of EPSCs were 28.2% higher in slices obtained from patients with MTLE compared to that in case of non-epileptic controls. We also examined spontaneous fast current transients (CTs) recorded from these pyramidal neurons under cell-attached configuration. The frequency of CTs increased in the absence of extracellular Mg2+ in brain slice preparations and was completely blocked by APV. We found that the frequency of CTs in pyramidal neurons were higher in case of MTLE samples compared to nonepileptic controls. This study suggests that enhanced endogenous activity of NMDA receptor contributes to excitability in pyramidal neurons of slice preparations obtained from patients with MTLE.