An NMDA-mediated component of excitatory synaptic input to dentate granule cells in 'epileptic' human hippocampus studied in vitro.

Recordings were made from human hippocampal tissue surgically removed for treatment of epilepsy. In 70% of cases, an N-methyl-D-aspartate (NMDA) receptor-mediated component was present in excitatory synaptic input to gyrus dentatus. NMDA receptors are normally present, but do not participate in low-frequency synaptic transmission, in this region of the mammalian brain. These findings suggest that recruitment of normally dormant excitatory amino acid receptors may be a feature of the epileptic brain.