Evidence for postsynaptic dopamine agonist effects of B-HT 920 in the presence of the dopamine D-1 agonist SKF 38393.
The ability of B-HT 920, a selective dopamine (DA) D-2 agonist, to stimulate postsynaptic DA receptors in brain was evaluated by assessing its ability to induce stereotypy and to increase locomotor activity in rats. When administered alone, B-HT 920 (0.03-3.0 mg/kg) did not induce stereotypy and produced only inhibition of locomotor activity, suggesting a lack of postsynaptic DA agonist actions. However, a different pattern of effects emerged when B-HT 920 was administered in combination with the selective DA D-1 agonist SKF 38393 (10 mg/kg): stereotypies (sniffing, licking, and gnawing) were induced and there was an inverted U-shaped function for locomotor activity. These data are consistent with the hypothesis that B-HT 920 has postsynaptic DA D-2 receptor agonist effects in normal rats that are revealed when D-1 receptor stimulation is also increased.
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001067:Appetite Depressants / Q000494:pharmacology*; D001381:Azepines / Q000494:pharmacology*; D001552:Benzazepines / Q000494:pharmacology*; D006120:Grooming / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D013239:Stereotyped Behavior / Q000187:drug effects
D000316:Adrenergic alpha-Agonists; D001067:Appetite Depressants; D001381:Azepines; D001552:Benzazepines; D011954:Receptors, Dopamine; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; C024763:talipexole