title: Peripheral opioids act as analgesics in bone cancer pain in mice.
abstract: Previous reports have shown that systemic administration of morphine can prevent the thermal hyperalgesia induced by the development of an osteosarcoma in C3H/HeJ mice after the implantation of NCTC 2472 cells. We show here that this type of hyperalgesia is also abolished by the local administration of morphine given at low doses (10 nmol), or the peripheral acting opioid receptor agonist loperamide (146 nmol). The analgesic effect of loperamide is prevented by the administration of the opioid receptor antagonist naloxone methiodide (10 mg/kg, i.p.), which is unable to cross the blood-brain barrier. These results provide evidence which supports the fact that peripheral opioids could be useful tools in the management of some types of cancer pain.
authors.affiliation: Laboratorio de Farmacología, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Facultad de Medicina, Universidad de Oviedo, C/Julián Clavería 6, 33006 Oviedo, Asturias, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Menéndez
authors.forename: Ana
authors.initials: A
authors.lastname: Lastra
authors.forename: Agustín
authors.initials: A
authors.lastname: Hidalgo
authors.forename: Alvaro
authors.initials: A
authors.lastname: Meana
authors.forename: Eva
authors.initials: E
authors.lastname: García
authors.forename: Ana
authors.initials: A
authors.lastname: Baamonde
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D001859:Bone Neoplasms / Q000150:complications*; D018929:Cell Culture Techniques; D006930:Hyperalgesia / Q000188:drug therapy / Q000209:etiology; D008139:Loperamide / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D012516:Osteosarcoma / Q000150:complications; D010146:Pain / Q000188:drug therapy* / Q000209:etiology*; D000644:Quaternary Ammonium Compounds
chemical_list: D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D000644:Quaternary Ammonium Compounds; D009270:Naloxone; D008139:Loperamide; C041269:N-methylnaloxone; D009020:Morphine