Structural determinants of selective affinity for brain D-1 dopamine receptors within a series of 1-phenyl-1H-3-benzazepine analogues of SK&F 38393 and SCH 23390.
A series of 1-phenyl-1H-3 benzazepine analogues of the D-1 agonist SK&F 38393 and of the D-1 antagonist SCH 23390 were compared for their relative abilities to displace the binding of [3H]piflutixol and [3H]spiperone to striatal D-1 and D-2 receptors respectively. The benzazepine analogues varied in substitutions at the 3- and 7-positions which distinguish SK & 38393 from SCH 23390. Substitutions at these positions critically influenced affinity for D-1 receptors over a 2000-fold range but influenced affinity for D-2 receptors over only a 30-fold range. 7-Substituents prominently increased affinity and selectivity for D-1 receptors with a rank order of Br = Cl much greater than CH3 greater than H greater than OH. 3-Methylation had a less marked and less selective action to increase affinity for D-1 receptors. Such structural relationships may aid the definition of the topography of brain D-1 receptors and the development of improved selective agents.
O'Boyle
K M
KM
Waddington
J L
JL
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000818:Animals; D014150:Antipsychotic Agents / Q000378:metabolism / Q000494:pharmacology*; D001067:Appetite Depressants / Q000494:pharmacology*; D001552:Benzazepines / Q000494:pharmacology*; D001921:Brain / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000378:metabolism; D013134:Spiperone / Q000378:metabolism; D013892:Thioxanthenes / Q000378:metabolism
D014150:Antipsychotic Agents; D001067:Appetite Depressants; D001552:Benzazepines; D011954:Receptors, Dopamine; D013892:Thioxanthenes; D013134:Spiperone; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; C015448:piflutixol