title: Seizure activity in photosensitive baboons following antidepressant drugs and the role of serotoninergic mechanisms.
abstract: Laboratroy and clinical evidence indicates that tricyclic antidepressants lower seizure threshold and in high doses may induce generalised seizures. In baboons with photosensitive epilepsy (Papio papio) the effects of 2 tricyclic antidepressants (imipramine and chlorimipramine) and of maprotiline and Nomi fensine have been studied (i.v. dose range 1-20 mg/kg. Imipramine, chlorimipramine and maprotiline (10 mg/kg i.v.) lowered seizure threshold to a comparable extent, whereas Nomifensine (10 mg/kg i.v-) did not enhance myoclinic responses to photic stimulation. Generalised seizures were seen 15-30 min after imipramine or chlorimipramine (20 mg/kg), and these two drugs showed no difference in their epileptogenicity. Administration of 5-hydroxytryptophan (25 mg/kg i.v.) 90 min before chlorimipramine or imipramine (10 mg/kg) completely blocked the usual augmentation of photically-induced epileptic responses. It is concluded that enhancement of serotoninergic activity following blockade of 5-HT re-uptake within the brain is unlikely to be responsible for enhanced myoclonic responses and epileptogenic seizures seen after tricyclic antidepressants. Nomifensine is significantly less epileptogenic than imipramine or chlorimipramine.
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D002997:Clomipramine / Q000494:pharmacology; D004569:Electroencephalography; D000882:Haplorhini; D007099:Imipramine / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D008376:Maprotiline / Q000494:pharmacology; D010215:Papio; D010775:Photic Stimulation; D012640:Seizures / Q000139:chemically induced* / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D012701:Serotonin / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors
chemical_list: D000928:Antidepressive Agents; D007546:Isoquinolines; D008376:Maprotiline; D012701:Serotonin; D006916:5-Hydroxytryptophan; D002997:Clomipramine; D007099:Imipramine