title: Phenytoin, an antiepileptic drug, competitively blocked non-NMDA receptors produced by Xenopus oocytes.
abstract: The blocking effect of phenytoin (PHT) and other antiepileptic agents on the glutamate receptors was investigated under voltage-clamp conditions using Xenopus oocytes that translated ddY-stock mouse brain mRNA. PHT shifted the concentration-response curve for kainate to right without significant block on the maximum response obtained, indicating that PHT competitively blocks the non-NMDA receptors. An apparent dissociation constant of PHT was 1.9 x 10(-4) M. The block was voltage-independent. Other antiepileptic agents examined hardly blocked the kainate responses except phenobarbital that blocked the responses. The possibility that the competitive block constitutes a part of the antiepileptic action of PHT was discussed.
authors.affiliation: Department of Molecular Biology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kawano
authors.forename: S
authors.initials: S
authors.lastname: Sashihara
authors.forename: T
authors.initials: T
authors.lastname: Mita
authors.forename: K
authors.initials: K
authors.lastname: Ohno
authors.forename: M
authors.initials: M
authors.lastname: Kawamura
authors.forename: K
authors.initials: K
authors.lastname: Yoshii
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D001667:Binding, Competitive / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists; D007608:Kainic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D010672:Phenytoin / Q000494:pharmacology*; D011061:Poly A / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017470:Receptors, Glutamate / Q000378:metabolism; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D014981:Xenopus
chemical_list: D000927:Anticonvulsants; D018691:Excitatory Amino Acid Antagonists; D012333:RNA, Messenger; D017470:Receptors, Glutamate; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D011061:Poly A; D010672:Phenytoin; D007608:Kainic Acid