title: Assessment of ropinirole as a reinforcer in rhesus monkeys.
abstract: BACKGROUND
  Ropinirole, a D(2)/D(3)/5-HT(1A) agonist, is used for the treatment of Parkinson's disease and restless leg syndrome, and is currently being evaluated as a treatment for cocaine dependence. However, there is little information available on ropinirole's reinforcing effects.
  
  
  METHODS
  The current study tested ropinirole in monkeys (n=7) trained to self administer cocaine on a fixed-ratio 25 (FR 25) schedule of reinforcement to determine if it would function as a reinforcer. In addition, a behavioral economics approach was used in four monkeys to compare the reinforcing effectiveness of ropinirole to cocaine.
  
  
  RESULTS
  Cocaine (0.01-0.3 mg/kg/injection) functioned as a reinforcer in all monkeys under the FR 25 schedule, and ropinirole (0.01-0.1mg/kg/injection) functioned as a reinforcer in all but one. Furthermore, cocaine was a more effective reinforcer than ropinirole as indexed by demand functions.
  
  
  CONCLUSIONS
  The current data indicate that ropinirole has reinforcing effects in monkeys, although its effectiveness as a reinforcer is relatively weak.
authors.affiliation: Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, The University of Mississippi Medical Center, Jackson, MS 39216, USA. kfreeman@umc.edu
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Freeman
authors.forename: David J
authors.initials: DJ
authors.lastname: Heal
authors.forename: Andrew C
authors.initials: AC
authors.lastname: McCreary
authors.forename: William L
authors.initials: WL
authors.lastname: Woolverton
mesh_terms: D000818:Animals; D003042:Cocaine / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects*; D003627:Data Interpretation, Statistical; D018491:Dopamine Agonists / Q000494:pharmacology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007211:Indoles / Q000494:pharmacology*; D007275:Injections, Intravenous; D008253:Macaca mulatta; D008297:Male; D017448:Receptors, Dopamine D2 / Q000819:agonists; D012055:Reinforcement Schedule; D012054:Reinforcement, Psychology; D012646:Self Administration
chemical_list: D018491:Dopamine Agonists; D018765:Dopamine Uptake Inhibitors; D007211:Indoles; D017448:Receptors, Dopamine D2; C046649:ropinirole; D003042:Cocaine