Fig. 1

ET-1-induced scratching is effectively abolished by antagonizing the ET_A receptor. Wild-type (C57BL/6 J) mice were injected intradermally in the nape with either ET-1 (10 pmol, n = 6) or ET-1 together with ET_AR antagonist BQ-123 (10 pmol + 10 nmol, n = 6). a, b BQ-123 was very effective in reducing the total scratching frequency and duration and the scratching behavior was similar to vehicle-injected (saline) animals (n = 24, data from Supplementary Figure 1). c When the frequency results from (a) were analyzed over time with the BQ-123 treatment as a factor, it was seen that antagonist-treated mice scratched significantly less overall (indicated by significance bar on the far right), and post hoc analysis showed significant difference between treatment groups in the interval between 10 and 20 min. Results are presented as mean ± SEM. *P ≤ 0.05; ***P ≤ 0.001; n.s., not significant; 1-way ANOVA with Bonferroni multiple comparison (a, b); 2-way ANOVA with Bonferroni multiple comparison (c). Vehicle data in (a, b) is the same data as presented in Supplementary Figure 1a-1b