Models of simple partial and absence seizures in freely moving rats: action of ketamine.
The action of ketamine was studied in two models of seizures: a) bilateral neocortical discharges produced by topical application of pentylenetetrazol (model of simple partial seizures); and b) rhythmic spike-and-wave activity induced by systemic administration of pentylenetetrazol (model of absence seizures). Ketamine exerted biphasic effects. In the first model, the dose of 20 mg/kg ketamine significantly suppressed the ictal neocortical discharges (i.e., continuous spiking or ictal activity) accompanied by clonic motor seizures. However, at the dose of 40 mg/kg ketamine significantly accentuated the onset and increased the number of individual discharges (interictal spikes) in bilateral neocortical foci. In the model of rhythmic spike-and-wave activity, the lower dose of ketamine (20 mg/kg) decreased the number of rhythmic spike-and-wave episodes when compared to the higher dose (40 mg/kg) of ketamine, which increased the number of episodes. However, neither result differed significantly from control values. The present results suggest a dose-dependent action of ketamine: Lower doses (10 and 20 mg/kg in the rat) are able to suppress seizure activity, whereas a higher dose (40 mg/kg) potentiates the seizures. Moreover, the action of ketamine may be dependent upon the seizure model used. The study presents a new model of acute epileptic focus in freely moving rats.
Velísek
L
L
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Vondricková
R
R
Mares
P
P
D000818:Animals; D002540:Cerebral Cortex; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects; D004828:Epilepsies, Partial / Q000139:chemically induced* / Q000503:physiopathology; D004832:Epilepsy, Absence / Q000139:chemically induced* / Q000503:physiopathology; D007267:Injections; D007274:Injections, Intraperitoneal; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D010433:Pentylenetetrazole / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar
D007649:Ketamine; D010433:Pentylenetetrazole