title: Pain-relieving effects of processed Aconiti tuber in CCI-neuropathic rats.
abstract: Neuropathic pain is often refractory to conventional pain therapies and thus requires exploration of effective drugs. We evaluated if processed Aconiti tuber (PAT), a traditional oriental herbal medicine that has been used as an analgesic, relieves neuropathic pain in the rat chronic constriction injury (CCI) model. Ten to 14 days after CCI in the right hind paw, six groups of rats received oral placebo, or PAT at 0.5, 1, 2, 3, or 5 g/kg. Additional groups received oral PAT, 2 g/kg, after pretreatment with intraperitoneal naloxone; intraperitoneal nor-binaltorphimine (norBNI); or intrathecal norBNI. As indicators of mechanical allodynia and thermal hyperalgesia, the pressure threshold of paw withdrawal (PWT) in response to linearly increasing pressure, and latency to paw withdrawal (PWL) in response to radiant heat, were measured before and after drug administration. Oral PAT dose-dependently increased PWT and PWL, which had been decreased due to CCI. The increases in PWT and PWL by oral PAT were inhibited by intraperitoneal and intrathecal norBNI: a selective kappa-opioid receptor antagonist, but not by intraperitoneal naloxone. These results indicate that oral PAT can alleviate mechanical allodynia and thermal hyperalgesia, dose-dependently, via spinal kappa-opioid receptor mechanisms in a rat CCI neuropathic pain model.
authors.affiliation: Department of Anesthesiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors.forename: Hongmeng
authors.initials: H
authors.lastname: Xu
authors.forename: Hideko
authors.initials: H
authors.lastname: Arita
authors.forename: Masakazu
authors.initials: M
authors.lastname: Hayashida
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sekiyama
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hanaoka
mesh_terms: D031841:Aconitum; D000700:Analgesics / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use*; D007274:Injections, Intraperitoneal; D007278:Injections, Spinal; D008297:Male; D009271:Naltrexone / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D035281:Plant Tubers; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000187:drug effects / Q000378:metabolism; D012584:Sciatic Nerve / Q000601:surgery; D012585:Sciatica / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism
chemical_list: D000700:Analgesics; D004365:Drugs, Chinese Herbal; D017473:Receptors, Opioid, kappa; C088301:tsumura-shuchi-bushi-matsu; C051844:norbinaltorphimine; D009271:Naltrexone