title: Inhibition of 5-hydroxytryptamine-mediated behaviour by the putative 5-HT2 antagonist pirenperone.
abstract: The effect of pirenperone, a putative 5-HT2 receptor antagonist, on various 5-HT-mediated behavioural responses has been examined. The head twitch response in mice, induced by administration of carbidopa (25 mg/kg) followed by 5-hydroxytryptophan (5-HTP) (200 mg/kg), was inhibited in a dose-dependent manner by pirenperone, with an ED50 of 76 micrograms/kg. The appearance of head weaving, forepaw treading and hind-limb abduction, which followed the administration of tranylcypromine (5 mg/kg) plus L-tryptophan (100 mg/kg) or quipazine (50 mg/kg) to rats, was also inhibited by pretreatment with pirenperone (100 micrograms/kg). Pirenperone did not alter the rate of 5-HT synthesis in the rat brain. Whilst pirenperone (100 micrograms/kg) did decrease methamphetamine-induced locomotor activity in rats, a dose of haloperidol producing a similar inhibition of this response did not alter the 5-HT-mediated behaviour. It is suggested, therefore, that the currently used 5-HT-induced behavioural models are 5-HT2 receptor-mediated.
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D002230:Carbidopa / Q000494:pharmacology; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D010880:Piperidines / Q000494:pharmacology*; D011814:Quipazine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism; D012702:Serotonin Antagonists; D014191:Tranylcypromine / Q000494:pharmacology; D014364:Tryptophan / Q000494:pharmacology
chemical_list: D010880:Piperidines; D012702:Serotonin Antagonists; D012701:Serotonin; D014191:Tranylcypromine; D008694:Methamphetamine; D011814:Quipazine; D014364:Tryptophan; D006916:5-Hydroxytryptophan; D006220:Haloperidol; D002230:Carbidopa; C034177:pirenperone