Figure 8.

Concentrated citric acid at pH 3.5 but not at pH 5.5 induces paw-licking behavior that is ASIC1 independent. A, Each mouse was injected with either 5% formalin; 30 mm citrate, pH 5.5; or 100 mm citrate, pH 5.5 or 3.5, into one hindpaw, and the duration of paw licking over a period of 30 min was recorded; n = 6 per group, n.s. p > 0.05, ***p < 0.001, one-way ANOVA with a post hoc Tukey's test. B, C, Each mouse was injected with either 5% formalin, with or without amiloride (100 μm; B) or 100 mm citrate, pH 3.5, with or without amiloride (100 μm; C) into one hindpaw, and the duration of paw licking over a period of 30 min was recorded; n = 6 per group, n.s. p > 0.05, two-tailed Student's t test. D, wild-type mice (WT) or mice with homozygous ASIC1 deletion (ASIC1^−/−) were injected with 100 mm citrate, pH 3.5, into one hindpaw, and the duration of paw licking over a period of 30 min was recorded; n = 6 per group, n.s. p > 0.05, two-tailed Student's t test. n.s., Not significant.