title: Characterization of scratching behavior induced by intradermal administration of morphine and fentanyl in mice.
abstract: Itching is known as a commonly side effect of opioid administration. However, the relationship of opioid receptors to itching is unclear. In this study, we examined the effect of intradermal injection of morphine and fentanyl on the itching sensation. When injected intradermally into the rostral back of mice, morphine and fentanyl elicited scratching behavior. In addition, an opioid receptor antagonist, naloxone, and a peripherally restricted opioid receptor antagonist, naloxone methiodide, significantly suppressed morphine- and fentanyl-induced scratching behavior. Moreover, the morphine-induced scratching behavior was suppressed by histamine H(1) receptor antagonists, such as diphenhydramine, chlorpheniramine, epinastine and cetirizine. On the other hand, fentanyl-induced scratching behavior was not suppressed by histamine H(1) receptor antagonists. Additionally, scratching behavior induced by morphine and fentanyl were not suppressed by glucocorticoids (predonisolone and dexamethasone). In conclusion, opioid-induced itching may involve in peripheral opioid receptors. Moreover, histamine and arachidonic acid metabolites played no main role in opioid-induced scratching behavior.
authors.affiliation: Department of Medicinal Pharmacology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Tsushima-naka 1-1-1, Okayama 700-8530, Japan.
authors.forename: Atsuki
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Shoji
authors.initials: S
authors.lastname: Kuyama
authors.forename: Chiaki
authors.initials: C
authors.lastname: Kamei
authors.forename: Yukio
authors.initials: Y
authors.lastname: Sugimoto
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D005283:Fentanyl / Q000008:administration & dosage* / Q000009:adverse effects*; D006634:Histamine H1 Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D007271:Injections, Intradermal; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009020:Morphine / Q000008:administration & dosage* / Q000009:adverse effects*; D009270:Naloxone / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D009292:Narcotic Antagonists; D011537:Pruritus / Q000139:chemically induced* / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D011957:Receptors, Opioid / Q000378:metabolism
chemical_list: D000701:Analgesics, Opioid; D006634:Histamine H1 Antagonists; D006993:Hypnotics and Sedatives; D009292:Narcotic Antagonists; D011957:Receptors, Opioid; D009270:Naloxone; D009020:Morphine; D005283:Fentanyl