β-Alanine–induced more pain than itch in CCI models. A) The number of times biting in 20 min after injection of β-alanine (50 mM, 10 μl) in WT and MrgprD−/− mice without injury. B) The number of times licking in 20 min after injection of β-alanine (50 mM, 10 μl) in WT and MrgprD−/− mice without CCI. C) The biting behavior was unchanged between CCI models and controls after the injection of β-alanine (50 mM, 10 μl). D) The comparison of licking behavior after the injection of β-alanine (50 mM, 10 μl) between CCI models and controls. E) The mean ratio of licking behavior (the times biting compared to the sum of times licking and biting) in control mice after CCI for 7 d and in mice after CCI for 14 d. F) The times licking in 20 min after injection of β-alanine (50 mM, 10 μL) in WT and MrgprD−/− mice in CCI models. G) The times biting in 20 min after injection of β-alanine (50 mM, 10 μl) in WT and MrgprD−/− mice after CCI operation. H) The licking behavior after the injection of β-alanine (50 mM, 10 μl) in WT and TRPA1−/− mice without operation. I) Licking behavior after the injection of β-alanine (50 mM, 10 μl) in WT and TRPA1−/− mice after CCI (n = 8 for all experiments). *P < 0.05, **P < 0.01, ***P < 0.001, by (A–D, F–I) paired-sample Student’s t-test, littermate control; (E) 1-way repeated-measures ANOVA.