title: Direct relationship of brain concentration of methadone with analgesia in chronic morphine-implanted and acute naloxone-treated rats.
mesh_terms: D000698:Analgesia; D000818:Animals; D001921:Brain / Q000187:drug effects*; D008691:Methadone / Q000032:analysis / Q000037:antagonists & inhibitors*; D009020:Morphine / Q000008:administration & dosage*; D009270:Naloxone / Q000008:administration & dosage*; D051381:Rats
chemical_list: D009270:Naloxone; D009020:Morphine; D008691:Methadone