title: Tetrahydroprotoberberine--a new chemical type of antagonist of dopamine receptors.
abstract: In rats lesioned by unilateral micro-injection of 6-OHDA into substantia nigra, the apomorphine-induced contralateral rotation and the amphetamine-induced ipsilateral rotation were antagonized by THB, l-THP and haloperidol. Scopolamine reversed the antagonistic effect of THB against amphetamine. Thus, THB and l-THP exhibited the DA-receptor antagonistic property which was similar to that of haloperidol. l-SPD (10 mg/kg), however, only antagonized the amphetamine-challenged rotational response, while it could not antagonize, but potentiate, the apomorphine-challenged rotational response. So, l-SPD might be a partial agonistic antagonist of DA-receptors, and its effect was more potent than that of THB and l-THP. l-SPD would be ascertained further in clinic trial. From these results and others, the authors suggest that THPB is a new chemical type of antagonist of brain DA-receptors.
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001599:Berberine / Q000031:analogs & derivatives / Q000494:pharmacology; D001600:Berberine Alkaloids / Q000494:pharmacology*; D003342:Corpus Striatum / Q000502:physiology; D006220:Haloperidol / Q000494:pharmacology; D051381:Rats; D011954:Receptors, Dopamine / Q000187:drug effects*; D012601:Scopolamine / Q000494:pharmacology; D013378:Substantia Nigra / Q000502:physiology
chemical_list: D000470:Alkaloids; D014150:Antipsychotic Agents; D001600:Berberine Alkaloids; D011954:Receptors, Dopamine; D001599:Berberine; C010513:stepholidine; C014215:tetrahydropalmatine; C014845:berbine; D012601:Scopolamine; D006220:Haloperidol; C004645:canadine