Differential effects of early-life seizures on neuronal inhibition in the hippocampus of seizure-prone and seizure-resistant rats
Abstract
The aim of this study is to investigate the long-term physiological consequences of early-life seizures in rats of different genetic backgrounds. Rats bred to be prone (Fast) or resistant (Slow) to amygdala kindling were induced with status epilepticus (SE) on postnatal day (PND) 10 by injecting 3 mg/kg i.p. kainic acid; SE consisted of seizures for 2 h, including stage 5 seizures (lying down with four limb tonic-clonic convulsions). Littermates injected with the same volume of saline i.p. served as controls. On PND 40-55, population spikes (PSs) were recorded at the CA1 pyramidal cell layer in hippocampal slices in vitro following paired-pulse stimulation of the stratum radiatum. As compared to the saline-injected control Fast rats, seizure Fast rats showed a larger paired-pulse index (PPI = ratio of second PS to first PS) at 4 x threshold stimulus intensity, and 20-100 ms interpulse interval (IPI) (repeated measures ANOVA, P