Serotonin but not zonisamide inhibits theophylline-induced epileptiform activity in guinea pig hippocampal CA3 neurons.
To test the putative serotonin (5-HT)-like effect of zonisamide (ZNS) we employed xanthine-induced epileptiform activity in the hippocampus slice preparation from guinea pigs. In this model Na(+)- and T-type Ca(2+) channel blockers are hardly effective while 5-HT should be inhibitory. Bath application of 5-HT hyperpolarized neurons and abolished theophylline-induced epileptiform activity. In contrast, ZNS failed to alter epileptiform bursting. We conclude that 5-HT augmenting effects of ZNS are missing or are not sufficient to inhibit epileptiform activity in hippocampal slice preparations.
Thöne
Jan
J
Institute of Physiology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany. jan.thoene@klinikum-nuernberg.de
Wiemann
Martin
M
D000200:Action Potentials / Q000187:drug effects; D000704:Analysis of Variance; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004827:Epilepsy / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D006168:Guinea Pigs; D006624:Hippocampus / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology; D066298:In Vitro Techniques; D007555:Isoxazoles / Q000494:pharmacology / Q000627:therapeutic use*; D009433:Neural Inhibition / Q000187:drug effects; D009474:Neurons / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology / Q000627:therapeutic use*; D013806:Theophylline; D000078305:Zonisamide
D000927:Anticonvulsants; D007555:Isoxazoles; D012701:Serotonin; D000078305:Zonisamide; D013806:Theophylline