Evidence for involvement of both D1 and D2 receptors in maintaining cocaine self-administration

• Published in: Pharmacology, biochemistry and behavior Vol. 39; no. 4; p. 911
• Main Authors: Britton, D R, Curzon, P, Mackenzie, R G, Kebabian, J W, Williams, J E, Kerkman, D
• Format: Journal Article
• Language: English
• Published: United States 01-08-1991
• Subjects: Animals; Antipsychotic Agents - pharmacology; Benzamides - pharmacology; Benzazepines - pharmacology; Cocaine - pharmacology; Corpus Striatum - drug effects; Corpus Striatum - metabolism; Dopamine Antagonists; In Vitro Techniques; Male; Papaverine - analogs & derivatives; Papaverine - metabolism; Papaverine - pharmacology; Rats; Rats, Inbred Strains; Receptors, Adrenergic - drug effects; Receptors, Adrenergic - metabolism; Receptors, Dopamine - physiology; Receptors, Dopamine D1; Receptors, Dopamine D2; Receptors, Serotonin - drug effects; Receptors, Serotonin - metabolism; Reinforcement Schedule; Self Administration - psychology; Tetrahydroisoquinolines
• ISSN: 0091-3057
• DOI: 10.1016/0091-3057(91)90052-4

Rats trained to self-administer cocaine (0.75 mg/kg/infusion) on an FR-5 schedule were treated with selective D1 or D2 antagonists. A69045, a D1 antagonist with no appreciable affinity for 5-HT receptors increased cocaine self-administration to 147, 172 and 167% of baseline at doses of 2.5, 5.0 or 10.0 mumol/kg, SC respectively. SCH-23390 (0.007, 0.015 and 0.030 mumol/kg, SC) increased self-administration to 116, 147 and 165% of baseline, respectively. Both D1 antagonists decreased responding in some animals at the highest dose tested. The D2 antagonist YM-09151-2 showed a similar profile, increasing cocaine self-administration at 0.01 and 0.016 mumol/kg, SC and suppressing responding by most animals at the dose of 0.03 mumol/kg, SC. These data give further support to the hypothesis that both D1 and D2 receptors are involved in maintaining cocaine self-administration.