title: Comparative effects of Mitragyna speciosa extract, mitragynine, and opioid agonists on thermal nociception in rats.
abstract: This study sought to compare the effects of Mitragyna speciosa (Korth.) Havil. extract, alkaloids fraction, and mitragynine, a μ-opioid receptor agonist, to that of morphine and oxycodone in a test of thermal nociception. In Experiment 1, male Sprague-Dawley rats were administered test articles intraperitoneally (IP) 30 min prior to testing to compare the effects of M. speciosa articles to opioid reference compounds on the hotplate assay. Test articles were vehicle, 10 mg/kg morphine, 3 mg/kg oxycodone, 300 mg/kg M. speciosa extract, 75 mg/kg M. speciosa alkaloids fraction, or 30 mg/kg mitragynine. To mirror consumer usage, Experiment 2 sought to determine whether M. speciosa articles retained their biological activity when given orally (PO). Test articles were vehicle, 6 mg/kg oxycodone, 300 mg/kg M. speciosa extract, or 100mg/kg mitragynine with hotplate tests conducted 30 and 60 min after administration. Mitragynine produced antinociceptive effects similar to the reference opioid agonists when administered IP and PO routes. These data suggest that M. speciosa extracts containing significant quantities of mitragynine may warrant consideration for further studies in primate self-administration models to yield insight into the abuse liability of this commercially available product.
authors.affiliation: National Center for Natural Products Research, University of Mississippi, MS 38677, USA.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Carpenter
authors.affiliation: Department of Psychology, University of Mississippi, MS 38677, USA.
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Criddle
authors.affiliation: National Center for Natural Products Research, University of Mississippi, MS 38677, USA.
authors.forename: Helaina K
authors.initials: HK
authors.lastname: Craig
authors.affiliation: National Center for Natural Products Research, University of Mississippi, MS 38677, USA.
authors.forename: Zulfiqar
authors.initials: Z
authors.lastname: Ali
authors.affiliation: National Center for Natural Products Research, University of Mississippi, MS 38677, USA.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: National Center for Natural Products Research, University of Mississippi, MS 38677, USA.
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
authors.affiliation: National Center for Natural Products Research, University of Mississippi, MS 38677, USA; Department of Psychology, University of Mississippi, MS 38677, USA. Electronic address: pysufka@olemiss.edu.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Sufka
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D008297:Male; D032065:Mitragyna / Q000737:chemistry*; D009020:Morphine / Q000494:pharmacology; D059225:Nociception; D010098:Oxycodone / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D046948:Secologanin Tryptamine Alkaloids / Q000494:pharmacology*
chemical_list: D000701:Analgesics, Opioid; D010936:Plant Extracts; D046948:Secologanin Tryptamine Alkaloids; D009020:Morphine; D010098:Oxycodone; C001801:mitragynine
keywords: Hotplate; Intraperitoneal; Mitragyna speciosa (Korth.) Havil.; Mitragynine; Opioids; Oral