title: Progressive-ratio performance in the rhesus monkey maintained by opiate infusions.
mesh_terms: D000818:Animals; D003061:Codeine / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects*; D011431:Dextropropoxyphene / Q000494:pharmacology; D000882:Haplorhini; D003932:Heroin / Q000494:pharmacology; D008253:Macaca mulatta; D009294:Narcotics / Q000494:pharmacology*; D010423:Pentazocine / Q000494:pharmacology; D012055:Reinforcement Schedule; D012646:Self Administration; D013997:Time Factors
chemical_list: D009294:Narcotics; D003932:Heroin; D010423:Pentazocine; D011431:Dextropropoxyphene; D003061:Codeine