title: Three-choice discrimination in methadone maintenance patients: hydromorphone, naloxone, and saline.
mesh_terms: D003216:Conditioning, Operant / Q000187:drug effects; D004193:Discrimination Learning / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D004091:Hydromorphone / Q000494:pharmacology*; D008297:Male; D008691:Methadone / Q000627:therapeutic use*; D009270:Naloxone / Q000494:pharmacology*; D019966:Substance-Related Disorders / Q000188:drug therapy*
chemical_list: D009270:Naloxone; D004091:Hydromorphone; D008691:Methadone