title: Differential involvement of opioid receptors in intrathecal butorphanol-induced analgesia: compared to morphine.
abstract: The present experiments were performed to investigate the differential involvement of the opioid receptor subtypes in the antinociception of intrathecal (IT) butorphanol compared to IT morphine. A single dose (26 nmol) of IT nor-binaltorphimine (nor-BNI), beta-funaltrexamine (beta-FNA), and naltrindole (NTI) demonstrated a significant attenuation in the overall antinociception of IT butorphanol (52 nmol) or IT morphine (26 nmol). However, IT butorphanol elicits thermal antinociceptive effect through kappa > delta > or = mu, whereas morphine acts on mu >delta >> kappa. These results indicate that the antinociceptive effect of both IT butorphanol and IT morphine are mediated through mu, delta, and kappa opioid receptors in different relative orders.
authors.affiliation: Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson 39216, USA.
authors.forename: W
authors.initials: W
authors.lastname: Wongchanapai
authors.forename: B K
authors.initials: BK
authors.lastname: Tsang
authors.forename: Z
authors.initials: Z
authors.lastname: He
authors.forename: I K
authors.initials: IK
authors.lastname: Ho
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D002077:Butorphanol / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007278:Injections, Spinal; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011957:Receptors, Opioid / Q000187:drug effects*
chemical_list: D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D011957:Receptors, Opioid; C051844:norbinaltorphimine; D009271:Naltrexone; C024524:beta-funaltrexamine; D009020:Morphine; C055382:naltrindole; D002077:Butorphanol