Effects of piracetam on pentylenetetrazol-kindling development, hippocampal potentiation phenomena and kindling-induced learning deficit

Kindling is a generally accepted model for studying epilepsy development in the context of overexpression of processes of neuronal plasticity. In prev ious studies we have shown that establishment of kindling by repeated appli cation of subconvulsive doses of pentylenetetrazol (PTZ) also led to marked changes in hippocampal excitability and an impairment in learning behaviou r. With the intention of further investigating the relationship between kindli ng development, kindling-induced changes in excitability and learning defic its, rats were chemically kindled under pretreatment with the nootropic dru g piracetam. Furthermore, we tested acute piracetam effects on developed ki ndling seizures, the learning deficit and potentiation effects. At the inve stigated dose piracetam did not influence the kindling development. The kin dling-induced potentiation of hippocampal field potentials was significantl y diminished in piracetam-pretreated rats. Piracetam acutely injected compl etely antagonized this potentiation effect. Piracetam brought about a signi ficant improvement in impaired learning performance in rats pretreated duri ng kindling induction and acutely injected before the learning experiment, respectively. Possible correlations between the suppressing of the kindling related poten tiation in hippocampal structures by piracetam and its beneficial effect on learning impairment are discussed as antagonizing overexpression of potent iation in the course of kindling.