Development of long-lasting potentiation effects in the dentate gyrus during pentylenetetrazol kindling

In the present study kindling was induced in rats by repeated intraperitone al injection of pentylenetetrazol (PTZ) once every 48 h. The resulting seiz ure stages were registered after each PTZ application. The development of P TZ-induced kindling and the time course of possible potentiation effects in the dentate gyrus were examined. The efficacy of perforant pathway transmi ssion to the granule cells was tested in every second kindling session by m easuring the monosynaptic evoked field potentials recorded in the dentate g yrus following single test stimuli of the perforant pathway at different ri mes after PTZ injection in freely moving animals. The data suggest that est ablishment of a PTZ kindling is associated with the development of long-las ting potentiation of the field potentials. After completion of kindling it was demonstrated that kindled rats also show a diminished learning performa nce. The relationship between the development of potentiation phenomena in hippocampal substructures and learning impairment is discussed. (C) 2001 IS DN. Published by Elsevier Science Ltd. All rights reserved.