Possible dopamine agonist properties of quipazine maleate.
Though quipazine is widely regarded as a relatively pure serotonergic (5-HT) agonist and has been reported to have no dopamine (DA) agonist properties, it has produced stereotyped behavior (SB) associated with DA agonist arousal of striatal DA mechanisms. Since we observed a dose-related inhibition of quipazine induced stereotypy (QISB) by a centrally acting DA antagonist (haloperidol) that could not be mimicked by a central 5-HT receptor blocking agent (methysergide), it appeared likely that QISB is mediated by striatal DA mechanisms. This was further supported by our observing that QISB could be potentiated by a subthreshold dose of the central DA agonist apomorphine. In light of this, and the presence of abnormal movements seen concomitantly with QISB that are typically produced by intrastriatal injections of 5-HT agonists, it appears that QISB is a complex phenomenon. While QISB seems to be primarily due to the stimulation of DA mechanisms, the effect of quipazine on behavior appears to be a combined result of its effects on both DA and 5-HT mechanisms. Specifically, central striatal DA receptors appear to mediate QISB per se, while serotonergic mechanisms stimulated by quipazine inhibit its further development and produce extrapyramidal-like abnormal movements.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D006220:Haloperidol; D006801:Humans; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology*; D011814:Quipazine / Q000031:analogs & derivatives / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013239:Stereotyped Behavior / Q000187:drug effects / Q000502:physiology
D011804:Quinolines; D011814:Quipazine; D006220:Haloperidol; D001058:Apomorphine; D004298:Dopamine; D008784:Methysergide