Application of a B1R agonist in naïve skin. (A) Pain ratings during 8-minute iontophoresis of saline, bradykinin (BK), and des-Arg9-BK using a visual analogue scale (VAS; 0-100). (B) Area under the curve (AUC) from Fig 8A. Saline vs BK P < 0.001, BK vs des-Arg9-BK P = 0.02, n = 10, one-way repeated-measures analysis of variance (ANOVA) and Bonferroni post hoc analysis. Comparing BK, Des-Arg BK, and saline vehicle control in naïve skin. (C) Heat pain threshold (HPT). Saline vs BK P < 0.001, BK vs Des-Arg9-BK P = 0.018. (D) Mechanical pain threshold (MPT) saline vs BK P < 0.001, saline vs Des-Arg9-BK P = 0.04. Data log transformed and paired t-tests performed. (E) Flare area saline vs BK P < 0.001. (C) and (D) both use one-way ANOVA with Bonferroni post hoc analysis.