title: Evidence against the participation of mu- and kappa-opioid receptors in the analgesic activity of ketorolac in rats.
abstract: The possibility that activation of opioid receptors is involved in the analgesic activity of ketorolac was explored. The analgesic effects of ketorolac, of ketocyclazocine, the prototype kappa-agonist, and of morphine, the prototype mu-agonist, were assayed in the pain-induced functional impairment model in the rat. All three drugs induced a significant analgesic effect in this model. Naloxone was able to antagonize the effects of ketocyclazocine and morphine. However, the effect of ketorolac was not blocked by naloxone, although a high dose, 3.2 mg kg-1, capable of blocking kappa-receptors was used. It is concluded that activation of mu- or kappa-opioid receptors, by either a direct or an indirect mechanism, does not play a role in the analgesic activity of ketorolac.
authors.affiliation: Departamento de Farmacología y Toxicología del Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México DF, México.
authors.forename: V
authors.initials: V
authors.lastname: Granados-Soto
authors.forename: F J
authors.initials: FJ
authors.lastname: Flores-Murrieta
authors.forename: G
authors.initials: G
authors.lastname: Castañeda-Hernández
authors.forename: E
authors.initials: E
authors.lastname: Hong
authors.forename: F J
authors.initials: FJ
authors.lastname: López-Muñoz
mesh_terms: D000700:Analgesics / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D018712:Analgesics, Non-Narcotic / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D016314:Ethylketocyclazocine / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D020910:Ketorolac; D009020:Morphine / Q000494:pharmacology; D009069:Movement Disorders / Q000188:drug therapy; D009270:Naloxone / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D017473:Receptors, Opioid, kappa / Q000187:drug effects*; D017450:Receptors, Opioid, mu / Q000187:drug effects*; D013997:Time Factors; D014046:Tolmetin / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology
chemical_list: D000700:Analgesics; D018712:Analgesics, Non-Narcotic; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D009270:Naloxone; D016314:Ethylketocyclazocine; C012395:ketazocine; D009020:Morphine; D014046:Tolmetin; D020910:Ketorolac