Prostaglandin d2 induced potentiation of the anticonvulsant actions of phenobarbitone and phenytoin in rats. Role of serotonin.

Prostaglandin D2 (PGD2) produced a dose-related potentiation of the anticonvulsant actions of sub-effective doses of phenobarbitone and phenytoin against maximal electroshock-induced seizures in rats. PDG2-induced potentiation of phenobarbitone and phenytoin was significantly attenuated following pretreatment with centrally administered 5,6-dihydroxytryptamine, a selective neurotoxin for serotonergic neurones, p-chlorophenylalanine, a specific inhibitor of serotonin biosynthesis, and methysergide, a serotonin receptor antagonist, indicating that the potentiation was serotonin-mediated.