Is synaptic potentiation necessary for the development of kindling?
Maru E Department of Physiology, Nippon Medical School, Tokyo, Japan. Field potentials were recorded from the dentate gyrus of freely moving rats to examine the role of synaptic potentiation in the development of seizure susceptibility during rapid kindling. Kindling stimulations (10 Hz for 10 sec) were delivered to the perforant path at every 5 min for 5 or 6 hrs. This procedure produced a sustained depression of excitatory synaptic transmission at the perforant path-granule cell synapse during and after kindling. However, the kindling procedure resulted in the prolongation of afterdischarges and the development of interictal discharges originated from granule cells, indicating an increase in the seizure susceptibility of these neurons. These results indicate that synaptic potentiation is not a critical requirement for an increase in seizure susceptibility during rapid kindling, even if it has a facilitating effect on the development of kindling as suggested in previous studies.
