title: SCH 23390 blocks D-1 and D-2 dopamine receptors in rat neostriatum in vitro.
abstract: The agonistic and antagonistic effects of the new compound SCH 23390 were tested in functional model systems for the D-1 dopamine receptor and for the D-2 dopamine receptor in vitro. In superfused rat neostriatal slices the increase in the efflux of cyclic AMP was used as a parameter for D-1 receptor stimulation. D-2 receptor stimulation was measured as the decrease in the K+-evoked release of [3H]-acetylcholine. SCH 23390 had no agonistic activity in these two models. SCH 23390 was a potent antagonist of the stimulating effect of dopamine in the D-1 receptor model (apparent pA2 = 7.28). SCH 23390 also antagonized the effect of the D-2 receptor agonist LY 141865 in the D-2 receptor model (apparent pA2 = 6.34). This D-2 receptor antagonism proved to be of a competitive nature.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001067:Appetite Depressants / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology*; D001667:Binding, Competitive / Q000187:drug effects; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D004873:Ergolines / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000378:metabolism
chemical_list: D001067:Appetite Depressants; D001552:Benzazepines; D004873:Ergolines; D011954:Receptors, Dopamine; D019257:Quinpirole; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000242:Cyclic AMP; D000109:Acetylcholine; D015056:1-Methyl-3-isobutylxanthine