Figure 5.

Percentage of group III (A) and group IV (B) afferents activated by lactic acid at each pH level. More group IV afferents in the incision group responded to pH6.5 than the control group (* p=0.022 χ²-test). The total number of action potentials for each acid-responsive group III (C, control; D, incision) and group IV (E, control; F, incision) afferents. White horizontal lines in each graph indicate median values. There was a pH-dependent response (E, p = 0.013; F, p < 0.0001 Friedman’s test), and significant differences at pH 6.5 (## p < 0.001 vs. Baseline) and 7.0 (# p< 0.01 vs. Baseline, Dunn’s test) in the incision group (F). (G) The relation between acid responses and ongoing activity in group IV afferents from control and incision groups (* p=0.032 χ²-test). (H) Percentage of group IV afferents from control and incision groups with ongoing activity before and after pH 7.6 application. #=number