Lipid mediators have a variety of biological and pathophysiological functions in the skin. Especially well known are the metabolites of arachidonic acid that, when liberated from membrane phospholipids by phospholiplase A2, are involved in inflammation and pain. In the 1970s, prostaglandin (PG) E2, one such arachidonic acid metabolite, was reported to elicit itch, probably via histamine release, and to enhance experimentally evoked itch in humans (Hägermark and Strandberg 1977; Fjellner and Hägermark 1979). For a long time after that, only a few reports describing the roles of lipid mediators in pruritus have been published. One reason for such little progress in understanding the lipid itch mediators could be the lack of a reliable method for the behavioral evaluation of itch in animal experiments (Woodward et al. 1985). In 1995, pruritogenic substances, but not algogenic, were shown to elicit hind-paw scratching in mice, raising the possibility that scratching can be used as an index of itch response in rodents (Kuraishi et al. 1995). Animal experiments have revealed the involvement and roles of several lipid mediators for itch. In this chapter, the roles of lipid mediators in human and animal itch are explained.
© 2014 by Taylor & Francis Group, LLC.