Bursting in human epileptogenic neocortex is depressed by an N-methyl-D-aspartate antagonist

Intracellular recordings were performed in human neocortical neurons in 'in vitro' slices of brain samples excised during surgical treatment of epilepsy. In 14 of 38 neurons obtained from cortex exhibiting interictal spiking, bursts of action potentials arising from a synaptic depolarizing potential could be elicited by extracellular focal stimulation of adequate strength. The N-methyl-D-aspartate (NMDA) antagonist 2-amino-5-phosphonovalerate (APV) was capable of reducing and eventually blocking these bursts without affecting the repetitive firing evoked by depolarizing intracellular pulses or the membrane input resistance. These data suggest a role played by NMDA receptors in the bursting activity displayed by human neurons from spiking cortical areas and demonstrate a potential use of NMDA antagonists as antiepileptic drugs.