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Anticonvulsant Activity of Phenobarbital and Valproate Against Maximal Electroshock in Mice During Chronic Treatment with Caffeine and Caffeine Discontinuation
Author(s) -
Gasior Maciej,
Borowicz Kinga,
Buszewicz Grzegorz,
Kleinrok Zdzislaw,
Czuczwar Stanistaw Jerzy
Publication year - 1996
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/j.1528-1157.1996.tb00023.x
Subject(s) - caffeine , ed50 , anticonvulsant , phenobarbital , pharmacology , pharmacokinetics , dose–response relationship , chemistry , effective dose (radiation) , medicine , epilepsy , endocrinology , receptor , psychiatry , radiology
Summary: We evaluated the protective activity (expressed as ED 50 , values in mg/kg) of phenobarbital (PB, 120 min before testing) and valproate (30 min) alone or combined with caffeine in male mice with seizures induced by maximal electroshock (MES). Both antiepilep‐tic drugs (AEDs) were administered by intraperitoneal (i.p.) injection in a single dose to mice receiving intraperitoneal caffeine either in a single dose 30 min before the test or as pretreatment every 12 h for 3 and 14 days. In addition, we determined the ED 50 , values of the AEDs 24 and 72 h after 14–day treatment with caffeine. Finally, we studied the influence of a challenge dose of caffeine, injected in mice 24 and 72 h after 14 days of treatment with caffeine, on the protective activity of PB or VPA. Caffeine in a single dose of 23.1 mg/kg reduced the anticonvulsant effect of PB. Its protective activity was further impaired after 3 and 14 days of caffeine treatment. The ED 50 , for VPA was significantly increased both by the single dose of caffeine and by chronic treatment. The anticonvulsant activity of PB and VPA measured 24 and 72 h after 14–day treatment with caffeine did not differ from control values, but a challenge dose of caffeine injected 24 or 72 h after daily injections for 14 days resulted in a significant reduction in the protective activity of both AEDs. Measurement of the total plasma levels of caffeine, VPA, and PB did not suggest pharmacokinetic interactions as an explanation for our results. Our results indicate that chronic caffeine exposure may progressively reduce the antiepileptic potency of VPA and PB.