Changes in behavioural responses to the combined administration of D1 and D2 dopamine agonists in normosensitive and D1 supersensitive rats.
The selective D1 receptor stimulant SKF 38393 dose-dependently increased grooming time in rats without affecting locomotor activity or eliciting stereotyped behaviour. The selective D2 receptor agonist LY 171555 induced a dose-dependent increase in rat motility, a marked decrease in grooming time and a low occurrence of stereotyped behaviour. Concurrent administration of the two selective agonists induced high-degree stereotyped responses and reductions in locomotor and grooming behaviours. Rats withdrawn from repeated treatment with the selective D1 receptor blocker SCH 23390 (0.05 mg/kg twice daily for 21 days; 7 days of washout) did not exhibit any change of locomotor and grooming responses to threshold doses of LY 171555 and SKF 38393 given alone or in combination. On the contrary, a significantly greater occurrence of high-degree stereotyped responses to the combination of the two selective agonists was observed. The data support the view that D1 and D2 receptors have a cooperative role in the generation of stereotypies and suggest that D1 receptor supersensitivity needs D2 stimulation to be revealed.
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001067:Appetite Depressants / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004873:Ergolines / Q000494:pharmacology; D006120:Grooming / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000502:physiology; D013239:Stereotyped Behavior / Q000187:drug effects*; D013375:Substance Withdrawal Syndrome / Q000523:psychology
D014150:Antipsychotic Agents; 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