Kindling-like stimulus patterns induce epileptiform discharges in the guinea pig in vitro hippocampus

In the guinea pig in vitro hippocampal slice preparation, we have demonstrated that the repeated tetanic stimulation of the Schaffer collateral-commissural input to CA1 pyramidal neurones produces a progressive increase in the amplitude and duration of postsynaptic potentials, and stimulus-induced and spontaneous paroxysmal depolarization shifts (PDSs). Both the enhancement of synaptic transmission and the genesis of PDSs were reversibly blocked by the N-methyl-D-aspartate (NMDA) receptor antagonist (+/-)-2-amino-5-phosphonovalerate (APV). These results provide evidence that progressive, stimulation-induced long-term potentiation may serve as the trigger for kindling-induced epileptogenesis, and this process is dependent on the repeated activation of an APV-sensitive receptor.