Further evidence for an anomalous regulation of cortical 5-HT2 receptors: studies with 5-HT precursors.
Rats pretreated with either phenelzine (50 mg/kg 18 h and 12 mg/kg 90 min previously) or carbidopa (25 mg/kg 30 min previously) then given tryptophan or 5-hydroxytryptophan (5-HTP), developed wet-dog shakes which were more intense after 5-HTP. Cortical 5-HT2 receptors were significantly reduced within 3 h of tryptophan (150 or 500 mg/kg) given to phenelzine-treated rats. 5-HTP either did not affect (150 mg/kg) or slightly increased (350 mg/kg) 5-HT2 receptor numbers in rats pretreated with carbidopa. The response to 5-HTP (350 mg/kg) was not altered by pretreatment with alpha-methyl-p-tyrosine, haloperidol, propranolol or yohimbine.
Koshikawa
N
N
Department of Pharmacology, Nihon University School of Dentistry, Tokyo, Japan.
Koshikawa
F
F
Stephenson
J D
JD
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002230:Carbidopa / Q000494:pharmacology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D004347:Drug Interactions; D007650:Ketanserin / Q000494:pharmacology; D008297:Male; D010624:Phenelzine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects*; D014364:Tryptophan / Q000494:pharmacology
D011985:Receptors, Serotonin; D014364:Tryptophan; D007650:Ketanserin; D006916:5-Hydroxytryptophan; D002230:Carbidopa; D010624:Phenelzine