title: Harpagophytum procumbens extract potentiates morphine antinociception in neuropathic rats.
abstract: The association of opioids and non-steroidal anti-inflammatory drugs, to enhance pain relief and reduce the development of side effects, has been demonstrated. Given many reports concerning the antinociceptive and anti-inflammatory effects of Harpagophytum procumbens extracts, the aim of our study was to investigate the advantage of a co-administration of a subanalgesic dose of morphine preceded by a low dose of H. procumbens to verify this therapeutically useful association in a neuropathic pain model. Time course, registered with the association of the natural extract, at a dose that does not induce an antinociceptive effect, followed by a subanalgesic dose of morphine showed a well-defined antiallodynic and antihyperalgesic effect, suggesting a synergism as a result of the two-drug association. H. procumbens cooperates synergistically with morphine in resolving hyperalgesia and allodynia, two typical symptoms of neuropathic pain. The results support the strategy of using an adjuvant drug to improve opioid analgesic efficacy.
authors.affiliation: a Pharmacology and Toxicology Section, Department of Drug Sciences , University of Catania , Catania , Italy.
authors.forename: Carmela
authors.initials: C
authors.lastname: Parenti
authors.affiliation: b Medicinal Chemistry Section, Department of Drug Sciences , University of Catania , Catania , Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Aricò
authors.affiliation: c Department of Mathematics and Computer Science , University of Catania , Viale A. Doria 6, 95125 Catania , Italy.
authors.forename: Marzio
authors.initials: M
authors.lastname: Pennisi
authors.affiliation: d Department of Chemistry , "Sapienza" University of Rome , P.le A. Moro 5, 00185 Rome , Italy.|e Department of Environmental Biology , "Sapienza" University of Rome , P.le A. Moro 5, 00185 Rome , Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Venditti
authors.affiliation: a Pharmacology and Toxicology Section, Department of Drug Sciences , University of Catania , Catania , Italy.
authors.forename: Giovanna M
authors.initials: GM
authors.lastname: Scoto
mesh_terms: D000700:Analgesics / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D004357:Drug Synergism; D031684:Harpagophytum / Q000737:chemistry*; D006930:Hyperalgesia / Q000188:drug therapy; D008297:Male; D009020:Morphine / Q000494:pharmacology* / Q000627:therapeutic use; D009437:Neuralgia / Q000188:drug therapy*; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000700:Analgesics; D010936:Plant Extracts; D009020:Morphine
keywords: Harpagophytum procumbens; allodynia; hyperalgesia; opioid; persistent pain; synergism