title: Structure-affinity relationships of halogenated predicentrine and glaucine derivatives at D1 and D2 dopaminergic receptors: halogenation and D1 receptor selectivity.
abstract: Halogenation of the aporphine alkaloid boldine at the 3-position leads to increased affinity for rat brain D(1)-like dopaminergic receptors with some selectivity over D(2)-like receptors. A series of 3-halogenated and 3,8-dihalogenated (halogen=Cl, Br or I) derivatives of predicentrine (9-O-methylboldine) and glaucine (2,9-di-O-methylboldine) were prepared and assayed for binding at D(1) and D(2) sites. Halogenation of predicentrine led to strong increases in affinity for D(1)-like receptors, while the affinities for D(2)-like receptors were either practically unchanged or reduced three- to fourfold. Halogenated glaucine derivatives did not show any clear trend towards enhanced selectivity, and the affinities were poor and similar to or worse than the values previously recorded for glaucine itself. Together with earlier work on boldine derivatives, these results suggest that the 2-hydroxy group on the aporphine skeleton may determine a binding mode favoring D(1)-like over D(2)-like receptors, with enhanced affinity when the C-3 position is halogenated.
authors.affiliation: Department of Chemistry and Millennium Institute for Advanced Studies in Cell Biology and Biotechnology (CBB), Faculty of Sciences, University of Chile, Casilla 653, Santiago, Chile.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Asencio
authors.forename: Claudio
authors.initials: C
authors.lastname: Hurtado-Guzmán
authors.forename: John J
authors.initials: JJ
authors.lastname: López
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Cassels
authors.forename: Philippe
authors.initials: P
authors.lastname: Protais
authors.forename: Abdeslam
authors.initials: A
authors.lastname: Chagraoui
mesh_terms: D000818:Animals; D001060:Aporphines / Q000737:chemistry* / Q000494:pharmacology*; D006219:Halogens / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000187:drug effects*; D017448:Receptors, Dopamine D2 / Q000187:drug effects*; D013329:Structure-Activity Relationship
chemical_list: D001060:Aporphines; D006219:Halogens; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C067342:dicentrine; C005004:glaucine