Previous studies have reported persistent alterations in the electrophysiological characteristics of the CA1 region of the hippocampus after kindling. The present study examined the effects of perforant path kindling on O-Mg 2+ -induced epileptiform bursting in the CA1 region of hippocampal slices. The duration of evoked bursting was significantly longer in slices taken from kindled animals as compared to those taken from implanted, non-stimulated controls. No significant differences were found in spontaneous burst frequency between slices taken from kindled and control animals. These data suggest that perforant path kindling causes a persistent increase in hyperexcitability in the CA1 region of the hippocampus leading to a facilitation of evoked burst activity, perhaps through an enhancement in NMDA-related excitatory neurotransmission.