Background:
Abnormality in skin sensitivity may be responsible for unbearable itch in patients with atopic
dermatitis (AD).
Objectives:
We evaluated reactivity of NC/Tnd mice, a model for human AD, against various experimental stimulations.
Methods:
Several behavioral tests were performed after external stimuli were applied to NC/Tnd mice. Transient receptor
potential vanilloid subtype 1 (TRPV1) reactivity of neuronal cells collected from the dorsal root ganglions (DRG) was
analyzed with a Ca++ influx test. Finally, we evaluated suppressive effect of capsaicin on atopic itch of NC/Tnd mice.
Results:
Pain responses to heat, acidic stimulation, and capsaicin injection, which are transduced through TRPV1, were
decreased in NC/Tnd mice, when compared to two standard strains BALB/c and C57BL/6 mice. The reactivity of the
primary neurons isolated from DRG to capsaicin was markedly reduced in NC/Tnd mice. Topical application of histamine
evoked scratching in NC/Tnd mice as well as other two strains; however, the scratching intensities induced by nonhistamine
pruritogens were significantly lower in NC/Tnd mice comparing to the two strains. In conventional NC/Tnd
mice with AD, topical application of capsaicin reduced the scratching behavior.
Conclusion:
TRPV1 is associated with both pain and itch sensation; however, abnormalities in TRPV1 reactivity may involve
in severe itch in NC/Tnd mice.
Inhibition of the Warm Temperature–Activated Ca2+-Permeable Transient Receptor Potential Vanilloid TRPV3 Channel Attenuates Atopic Dermatitis