Chronic phenytoin and the stereotyped motor response induced by 5-methoxy-N,N-dimethyltryptamine in rats.
Male Sprague-Dawley rats were injected with phenytoin (PHT) once a day for 20 consecutive days and then tested as to their response to 5-methoxy-N,N-dimethyltryptamine (5-MDMT), a 5-hydroxytryptamine (5-HT) agonist, at 1 and 3 mg/kg on days 21 and 28. It was found that long-term PHT administration decreased the intensity of a stereotyped motor response induced by 5-MDMT (3 mg/kg) on day 21 but not on day 28. A single injection of PHT (25 mg/kg) did not modify the motor response induced by 5-MDMT (3 mg/kg) on day 21 but not on day 28. A single injection of PHT (25 mg/kg) did not modify the motor response induced by 5-MDMT (1.7, 3.2 mg/kg). It is suggested that PHT increases the functional availability of 5-HT before its receptors, and thereby causes 5-HT receptor subsensitivity.
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D004597:Electroshock; D006801:Humans; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology*; D010672:Phenytoin / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000031:analogs & derivatives* / Q000032:analysis; D013239:Stereotyped Behavior / Q000187:drug effects*; D014191:Tranylcypromine / Q000494:pharmacology; D014364:Tryptophan / Q000494:pharmacology
D008732:Methoxydimethyltryptamines; D011985:Receptors, Serotonin; D012701:Serotonin; D014191:Tranylcypromine; D010672:Phenytoin; D014364:Tryptophan