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

Abstract

Kindling is a generally accepted model for studying epilepsy development in the context of overexpression of processes of neuronal plasticity. In previous studies we have shown that establishment of kindling by repeated application of subconvulsive doses of pentylenetetrazol (PTZ) also led to marked changes in hippocampal excitability and an impairment in learning behaviour. With the intention of further investigating the relationship between kindling development, kindling-induced changes in excitability and learning deficits, rats were chemically kindled under pretreatment with the nootropic drug piracetam. Furthermore, we tested acute piracetam effects on developed kindling seizures, the learning deficit and potentiation effects. At the investigated dose piracetam did not influence the kindling development. The kindling-induced potentiation of hippocampal field potentials was significantly diminished in piracetam-pretreated rats. Piracetam acutely injected completely antagonized this potentiation effect. Piracetam brought about a significant improvement in impaired learning performance in rats pretreated during kindling induction and acutely injected before the learning experiment, respectively. Possible correlations between the suppressing of the kindling related potentiation in hippocampal structures by piracetam and its beneficial effect on learning impairment are discussed as antagonizing overexpression of potentiation in the course of kindling.

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

“…Therefore, it can be assumed that the ability of the neurones to react to a sufficient stimulus with a plastic change in excitability was continually enhanced. Moreover, as our previous results indicate, this change in reactivity was long-lasting even when PTZ application was interrupted for four weeks (Rü thrich et al, 1996(Rü thrich et al, , 1999. Such reactions were also recently described by .…”

Promnesic effects of Ptychopetalum olacoides in aversive and non-aversive learning paradigms

“…However, it has been suggested that oxiracetam also modulates glutamatergic transmission and protein kinase C (PKC) (Raiteri et al, 1992;Fordyce et al, 1995), while aniracetam and piracetam potentiate AMPA receptor mediated ion conductance and metabotropic glutamate receptor activity (Gouliaev and Senning, 1994;Johansen et al, 1995;Noorbala et al, 1999;Pittaluga et al, 1999;Ruthrich et al, 1999). Therefore, the mechanism of action responsible for memory facilitation by nootropic drugs in not fully known, and may involve various neurotransmitters.…”

Protective effect of rutin on cognitive impairment caused by phenytoin

“…PIM belongs to pyrrolidones group most of which are known to influence cholinergic functions. [ 24 25 ] Along with rutin, flavonoids and many members of this group have varying action on cholinergic system. In this study, AChE activity was reduced by PIM as well as by rutin in brain.…”