Effect of a subconvulsant dose of kainic acid on thresholds for phenomena elicited by electrical stimulation of sensorimotor cortex in rats

Nonconvulsive Seizures Result in Behavioral but Not Electrophysiological Changes in Developing Rats

“…This is in agreement with our other data: a subconvulsive dose of KA led to changes in the thresholds for elicitation of cortical epileptic afterdischarges in adult rats (17,18) and to changes in elevated plus maze performance in immature animals (20). These findings are in sharp contrast to the literature, where even in adult animals motor seizures are taken as a necessary prerequisite of functional and morphological changes after KA administration.…”

“…It is in agreement with the literature that even convulsive doses of KA do not elicit acute morphological changes when applied before PD 18 (10). Nonconvulsive, limbic seizures elicited by KA without any neuronal death were also described in adult rats (18,24). Our electrophysiological experiments did not demonstrate long-term potentiating effects of KA-induced nonconvulsive seizures on cortical epileptic afterdischarges.…”

“…Data on consequences of nonconvulsive seizures that do not progress into motor seizures are scarce. We started to study this problem in adult rats and our results indicate acute as well as longer-lasting changes in electrophysiological (cortical afterdischarges (17,18)) as well as behavioral (open field (19), elevated plus maze (20)) measures. The aim of the present study was to analyze possible functional changes after kainic acid-induced nonconvulsive seizures in rat pups.…”

“…We studied not only cortical afterdischarges but also spontaneous behavior in an open field as well as neocortical and hippocampal morphology 1 and 2 weeks after nonconvulsive seizures. These intervals were chosen on a basis of our positive findings at similar intervals in adult rats (18).…”

Interaction of Excitatory Amino Acid Agonists with Cortical Afterdischarges in Developing Rats

“…Therefore, we used an opposite way to determine the participation of NMDA and non-NMDA receptors in genesis of different types of cortical epileptic afterdischarges in developing brain: electrical stimulation was combined with subconvulsant doses of excitatory amino acid agonists. We have already tried this method in adult rats using kainic acid as a typical agonist, and we have shown that individual components of the afterdischarges might be influenced differently (9,10). A usefulness of this access was demonstrated also in immature rats with the adenosine antagonist aminophylline (11).…”