Response requirements and unit dose modify the effects of GBR 12909 on cocaine-maintained behavior.
Previous studies found that GBR 12909 can decrease cocaine-maintained responding at doses that do not affect food-maintained responding. In this study, the effects of GBR 12909 (0.3-3.0 mg/kg) were further examined by varying the response requirement and unit dose of cocaine. Rhesus monkeys earned food or cocaine under a multiple fixed-ratio (FR) schedule. The FR for food was always 30, but the FR for cocaine was varied from 10-130 and the unit dose was varied from 5.6-56.0 microg/kg per injection. Doses of GBR 12909 were tested in an ascending order, for 5 consecutive sessions each. GBR 12909 selectively decreased cocaine-maintained responding in all monkeys in at least 1 condition. These effects were enhanced with large response requirements and/or small unit doses. The results demonstrate that environmental variables can influence the selectivity of GBR 12909's effects and contribute to a growing debate concerning the evaluation of potential pharmacotherapies for drug abuse.
Stafford
D
D
Department of Pharmacology and Experimental Therapeutics, Louisiana State University Medical Center, Shreveport 71130, USA.
Rice
K C
KC
Lewis
D B
DB
Glowa
J R
JR
D000818:Animals; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D003042:Cocaine / Q000008:administration & dosage*; D019970:Cocaine-Related Disorders / Q000188:drug therapy*; D004195:Disease Models, Animal; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005260:Female; D008253:Macaca mulatta; D008297:Male; D010879:Piperazines / Q000494:pharmacology / Q000627:therapeutic use*
D000697:Central Nervous System Stimulants; D018765:Dopamine Uptake Inhibitors; D010879:Piperazines; C043425:vanoxerine; D003042:Cocaine