title: Quipazine-induced head-twitch in mice.
abstract: Quipazine has been reported to be a direct serotonin receptor agonist. In this laboratory, quipazine produced head-twitch in mice similar to that produced by the serotonin precursor, 5-hydroxytryptophan (5-HTP). Three antiserotonergic drugs (methiothepin, methysergide, and cinanserin) antagonized both the 5-HTP and quipazine-induced head-twitch responses. In addition, the quipazine response was significantly potentiated by a monoamine oxidase (MAO) inhibitor, pargyline. Since it is not likely that quipazine itself is metabolized by MAO, these results suggested that quipazine might cause release of endogenous serotonin. Parachlorophenylalanine, a serotonin depletor, significantly antagonized the potentiation of quipazine by the MAO inhibitor but failed to antagonize the head-twitch produced by quipazine itself. The present studies suggest that quipazine influences serotonin receptors in the brain to produce head-twitch by two mechanisms of action: (1) by direct serotonin receptor activation, and (2) indirectly by causing a release of endogenous serotonin.
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D002928:Cinanserin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D010134:Fenclonine / Q000494:pharmacology; D006257:Head; D008297:Male; D008719:Methiothepin / Q000494:pharmacology; D008784:Methysergide / Q000494:pharmacology; D051379:Mice; D009068:Movement / Q000187:drug effects*; D010293:Pargyline / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology*; D011985:Receptors, Serotonin; D012701:Serotonin / Q000378:metabolism
chemical_list: D010879:Piperazines; D011804:Quinolines; D011985:Receptors, Serotonin; D012701:Serotonin; D008719:Methiothepin; D010293:Pargyline; D006916:5-Hydroxytryptophan; D002928:Cinanserin; D010134:Fenclonine; D008784:Methysergide