Background: Itching in humans is attenuated by mu-opioid receptor antagonists. ICR mice display increases in scratching behavior upon induction of IgE-mediated passive cutaneous anaphylaxis (PCA), or intradermal injection of compound 48/80 or histamine.
Methods: Cutaneous reactions were induced in ICR mice by IgE-mediated PCA, compound 48/80 and histamine, and the scratching behavior associated with the cutaneous reactions was evaluated.
Results: Naloxone and nalmefene reduced the incidence of scratching behavior associated with PCA. Naloxone also inhibited the induction of scratching behavior caused by compound 48/80 and histamine. Naloxone did not affect the increase in vascular permeability caused by PCA and injection of compound 48/80.
Conclusion: Scratching behavior in mice may be induced by a sensation or a mechanism similar to itching in humans and should become a useful model for examining itching in humans.
Copyright 2000 S. Karger AG, Basel