In vitro hippocampal slices were prepared from control and commissural-kindled rats and the inhibitory processes of the dentate granule cells were assessed using paired perforant path stimulation. An early (20 ms) Cl(-)-dependent and a late (200 ms-8 s) Cl(-)-independent inhibition were shown to be present in the dentate. Enhancement of the late Cl(-)-insensitive inhibition was observed following the establishment of commissural kindling and persisted for periods of up to eight weeks following the last seizure.