title: Effects of serotonin receptor agonists and antagonists on schedule-controlled behavior of squirrel monkeys.
abstract: The behavioral effects of the serotonin (5-HT) precursor l-5-hydroxytryptophan (l-5-HTP) and the phenylpiperazine 5-HT agonists 6-chloro-2-(1-piperazinyl)pyrazine (MK-212), 1-(m-trifluromethylphenyl) piperazine (TFMPP), 1-(m-chlorophenyl)piperazine (CPP) and 2-(1-piperazinyl)quinoline (quipazine) were compared with those of the putative 5-HT antagonists metergoline, methysergide, cyproheptadine, cinanserin and ketanserin under a multiple 5-min fixed-interval schedule of food or electric shock presentation in squirrel monkeys. Intramuscular administration of l-5-HTP (0.3-17 mg/kg), MK-212 (0.01-1.0 mg/kg), TFMPP and CPP (0.03-10 mg/kg) produced dose-related decreases in responding under both the food- and shock-presentation schedules. Quipazine differed from the other 5-HT agonists in that it increased shock-maintained behavior at doses (0.1-1.0 mg/kg) that decreased responding maintained by food. The 5-HT antagonists produced mixed behavioral effects. Metergoline (0.03-1.0 mg/kg), cyproheptadine (0.1-1.0 mg/kg) and cinanserin (1.0-10 mg/kg) produced dose-related increases in responding maintained by food, whereas only metergoline and methysergide increased behavior maintained by shock presentation. The prototype 5-HT2-receptor ligand ketanserin (0.3-10 mg/kg) differed from the other 5-HT antagonists in that it decreased behavior maintained by either event. Thus, performances maintained by food or shock presentation reveal both qualitative and quantitative differences in the behavioral effects of 5-HT receptor agonists and antagonists.
authors.forename: L S
authors.initials: LS
authors.lastname: Brady
authors.forename: J E
authors.initials: JE
authors.lastname: Barrett
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D002928:Cinanserin / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects; D003533:Cyproheptadine / Q000494:pharmacology; D004597:Electroshock; D005260:Female; D007650:Ketanserin; D008297:Male; D008711:Metergoline / Q000494:pharmacology; D008784:Methysergide / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011719:Pyrazines / Q000494:pharmacology; D011814:Quipazine / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000378:metabolism*; D012453:Saimiri
chemical_list: D010879:Piperazines; D010880:Piperidines; D011719:Pyrazines; D011985:Receptors, Serotonin; D008711:Metergoline; C018406:1-(3-trifluoromethylphenyl)piperazine; D003533:Cyproheptadine; D011814:Quipazine; C014896:6-chloro-2-(1-piperazinyl)pyrazine; D007650:Ketanserin; D006916:5-Hydroxytryptophan; C031503:phenylpiperazine; D002928:Cinanserin; C015068:1-(3-chlorophenyl)piperazine; D008784:Methysergide