Place conditioning with the dopamine D₁-like receptor agonist SKF 82958 but not SKF 81297 or SKF 77434

While self-administration and place conditioning studies have shown that dopamine D₂-like receptor agonists produce reward-related learning, the, effects of dopamine D₁-like receptor agonists remain equivocal. The present study tested three dopamine D₁-like receptor agonists for their ability to induce a place preference. Like control rats treated with amphetamine (2.0 mg/kg i.p.), rats treated with SKF 82958 (±-6-chloro-7,8-dihydroxy-3-allyl-1-phenyl-2,3,4,5- tetrahydro-1-phenyl-1H-3-benzazepine hydrobromide; 0.05 but not 0.01, 0.025, 0.075, or 0.10 mg/kg s.c. and/or i.p.) during conditioning showed a significant increase in the amount of time spent on the drug-paired side during the drug free test. Neither SKF 81297 (±-6-chloro-7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide; 0.25, 0.50, 1.0, 2.0, and 4.0 mg/kg i.p.) nor SKF 77434 (±-7,8-dihydroxy-3-allyl-1-phenyl-2,3,4,5-tetrahydro-1H-3- benzazepine hydrochloride; 0.20, 1.0, 5.0, and 10.0 mg/kg i.p.) produced place conditioning. Significant increases in locomotion were seen at some doses of all drugs. Results show for the first time that systemic administration of a dopamine D₁-like receptor agonist produces a place preference and are consistent with previous findings showing that dopamine D₁-like receptor activation produces reward-related learning.