Mouse model of touch-evoked itch (alloknesis)

Tasuku Akiyama, Mirela Iodi Carstens, Akihiko Ikoma, Ferda Cevikbas, Martin Steinhoff, Earl Carstens

Research output: Contribution to journalArticlepeer-review

57 Scopus citations

Abstract

Lightly touching normal skin near a site of itch can elicit itch sensation, a phenomenon known as alloknesis. To investigate the neural mechanisms of alloknesis, we have developed an animal model. Low-threshold mechanical stimulation of the skin normally does not elicit any response in naive C57/BL6 mice. Following acute intradermal (i.d.) injection of histamine in the rostral back, mechanical stimulation 7 mm from the injection site elicited discrete hindlimb scratch bouts directed toward the stimulus. This began at 10 minutes and peaked 20-40 minutes post histamine injection, declining over the next hour. Histamine itself elicited bouts of scratching not associated with the mechanical stimulus, which ceased after 30 minutes. Histamine- and touch-evoked scratching was inhibited by the μ-opiate antagonist naltrexone. Touch-evoked scratching was observed following i.d. 5-HT (5-hydroxytryptamine), a protease-activated receptor (PAR)-4 agonist, and an MrgprC11 agonist BAM8-22, but not chloroquine or a PAR-2 agonist. The histamine H1 receptor antagonist terfenadine prevented scratching and alloknesis evoked by histamine, but not 5-HT, a PAR-4 agonist or an MrgprC11 agonist. In mice with experimental dry skin, there was a time-dependent increase in spontaneous and touch-evoked scratching. This animal model appears to be useful to investigate neural mechanisms of itch and alloknesis.

Original languageEnglish (US)
Pages (from-to)1886-1891
Number of pages6
JournalJournal of Investigative Dermatology
Volume132
Issue number7
DOIs
StatePublished - Jul 2012

ASJC Scopus subject areas

  • Dermatology
  • Biochemistry
  • Cell Biology
  • Molecular Biology

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