H. Kawano et al., PHENYTOIN, AN ANTIEPILEPTIC DRUG, COMPETITIVELY BLOCKED NON-NMDA RECEPTORS PRODUCED BY XENOPUS-OOCYTES, Neuroscience letters, 166(2), 1994, pp. 183-186
The blocking effect of phenytoin (PHT) and other antiepileptic agents
on the glutamate receptors was investigated under voltage-clamp condit
ions using Xenopus oocytes that translated ddY-stock mouse brain mRNA.
PHT shifted the concentration-response curve for kainate to right wit
hout significant block on the maximum response obtained, indicating th
at PHT competitively blocks the non-NMDA receptors. An apparent dissoc
iation constant of PI-IT was 1.9 x 10(-4) M. The block was voltage-ind
ependent. Other antiepileptic agents examined hardly blocked the kaina
te responses except phenobarbital that blocked the responses. The poss
ibility that the competitive block constitutes a part of the antiepile
ptic action of PHT was discussed.