title: The effects of chronic treatment with a calcium channel antagonist on two types of generalized epilepsies in rats.
abstract: Although calcium antagonists possess antiepileptic properties in various models of epilepsy, their role after chronic administration and in models for generalized absence epilepsy has not been studied. Twenty-four male Wistar rats, aged 84-94 weeks, were chronically provided with EEG electrodes. Two groups received dietary nimodipine (860 ppm) for 14 and 21 weeks, respectively, while a control group received the same rat chow without nimodipine. The EEG was recorded for 3 h to establish the effects of nimodipine on spike-wave discharges. Next, 50 mg/kg pentylenetetrazol (PTZ) was injected to establish the effects on convulsive epilepsy, and the EEG was recorded for 30 min. All animals had spontaneous spike-wave discharges (SWD), but there were no differences between the three groups. However, chronic nimodipine treatment had a significant effect on PTZ-induced seizures: the group that had been treated with nimodipine for 21 weeks showed significantly more and longer-lasting seizures than the control group. The facilitating effects of chronically administered of nimodipine on PTZ-induced seizures are striking and opposite to those reported in the literature. In a second study, nimodipine was administered acutely, but no effects of nimodipine on PTZ-induced epilepsy could be detected. It can be concluded that chronic dietary administration of a calcium antagonist induces different effects on PTZ-induced seizures than acute administration in aged Wistar rats with spontaneous occurring SWD.
authors.affiliation: Department of Psychology, University of Nijmegen, The Netherlands.
authors.forename: E L
authors.initials: EL
authors.lastname: van Luijtelaar
authors.forename: N
authors.initials: N
authors.lastname: Ates
authors.forename: F J
authors.initials: FJ
authors.lastname: van der Staay
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004032:Diet; D004569:Electroencephalography / Q000187:drug effects; D004832:Epilepsy, Absence / Q000503:physiopathology; D004829:Epilepsy, Generalized / Q000139:chemically induced / Q000235:genetics / Q000503:physiopathology*; D004830:Epilepsy, Tonic-Clonic / Q000503:physiopathology; D008297:Male; D009553:Nimodipine / Q000494:pharmacology*; D010433:Pentylenetetrazole; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002121:Calcium Channel Blockers; D009553:Nimodipine; D010433:Pentylenetetrazole