Figure 1.

SADBE challenge induced CHS and spontaneous site-directed behaviours in previously sensitized mice. (A) In comparison with pre-challenge values, the thickness of calf skin was significantly increased 24 h after the second SADBE challenge (n = 13 mice) whereas applications of acetone alone (vehicle) had no significant effect (n = 6) (paired t-test). (B) After SADBE challenge of the calf, cumulative durations of spontaneous biting and licking of the calf were each significantly increased over pre-challenge (Pre) values (n = 20) but not after applications of acetone (n = 6) (repeated measures analysis of variance with Bonferroni adjustments). (C) After SADBE challenge of the cheek, the number of bouts of spontaneous scratching and wiping were each significantly increased over pre-challenge values (n = 10) whereas the acetone vehicle itself had no significant effect (n = 6) (repeated measures analysis of variance with Bonferroni adjustments). (D) SADBE challenge to the nape of the neck in previously sensitized mice evoked significantly fewer bouts of site-directed scratching in MRGPRA3^GFP-Cre;ROSA26^DTR mice with selective ablation of MRGPRA3⁺ neurons (n = 7) than control ROSA26^DTR mice (n = 8) (unpaired t-test).*P < 0.05.