title: Blockade of the discriminative stimulus effects of cocaine in rhesus monkeys with the D1 dopamine antagonist SCH 23390.
abstract: To investigate the role of D1 dopamine receptors in the discriminative stimulus effects of cocaine, two rhesus monkeys were trained in a two-lever, food-reinforced, drug discrimination paradigm to discriminate cocaine (0.2 mg/kg, IM) from saline. Administration of various doses of cocaine resulted in a dose-related increase in the percentage of responses that occurred on the drug-appropriate lever. Administration of the D1 antagonist SCH 23390 20 min before cocaine reduced drug-appropriate responding from 100% to 0% in all subjects and increased by 4-8-fold the cocaine dose necessary to induce drug-appropriate responding. A mutual antagonism of the rate-decreasing effects of cocaine and SCH 23390 was also observed. These findings suggest that D1 receptors play a significant role in the discriminative stimulus and rate-decreasing effects of cocaine.
mesh_terms: D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001552:Benzazepines / Q000494:pharmacology*; D003042:Cocaine / Q000494:pharmacology*; D004193:Discrimination Learning / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D008253:Macaca mulatta; D012055:Reinforcement Schedule; D012646:Self Administration
chemical_list: D014150:Antipsychotic Agents; D001552:Benzazepines; D003042:Cocaine