SCH 23390 blocks D-1 and D-2 dopamine receptors in rat neostriatum in vitro

• Published in: Naunyn-Schmiedeberg's archives of pharmacology Vol. 327; no. 2; p. 180
• Main Authors: Plantjé, J F, Daus, F J, Hansen, H A, Stoof, J C
• Format: Journal Article
• Language: English
• Published: Germany 01.09.1984
• Subjects: 1-Methyl-3-isobutylxanthine - pharmacology; 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; Acetylcholine - metabolism; Animals; Appetite Depressants - pharmacology; Benzazepines - pharmacology; Binding, Competitive - drug effects; Corpus Striatum - drug effects; Corpus Striatum - metabolism; Cyclic AMP - metabolism; Ergolines - pharmacology; In Vitro Techniques; Kinetics; Male; Quinpirole; Rats; Rats, Inbred Strains; Receptors, Dopamine - drug effects; Receptors, Dopamine - metabolism
• ISSN: 0028-1298
• DOI: 10.1007/BF00500914

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.