Excitability cycles of epileptic after-discharges in rats.
An epileptic seizure is regularly followed by a postictal depression and then by a phase of increased excitability. The time course of these two phases was described for two types of epileptic after-discharges induced by stimulation of the hippocampus and/or the thalamus in acute experiments in rats. Using hippocampal stimulation, an interval of 10 min was necessary for induction of the second self-sustained after-discharge (SSAD) of the same duration as the first one. Significant prolongation of the second SSAD appeared with a 30-min interstimulation interval. The spike-and-wave rhythm induced by stimulation of thalamic nuclei exhibited a shorter refractory phase - up to 5 min - and also the facilitation took place sooner: with 15-min intervals a significant increase in duration of SSAD was recovered. The results are discussed in connection with the kindling model of epilepsy.
Mares
P
P
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Maresová
D
D
D000818:Animals; D004558:Electric Stimulation; D004566:Electrodes; D004827:Epilepsy / Q000503:physiopathology*; D006624:Hippocampus / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013788:Thalamus / Q000503:physiopathology*