Fig. 3.  The responses of acid-sensing ion channel 2 (ASIC2) knockout (KO; n = 13) and wild-type (WT; n = 17) mice did not differ after spinal nerve ligation (SNL). Data are shown as mean ± SE in all figures. (A ) SNL resulted in significant heat hyperalgesia in the ipsilateral (ipsi) paw, but no response difference was apparent based on genotype of the animals. ASIC2 KO and WT mice had comparable decreases in response latency (relative to baseline levels) after the nerve injury. The average withdrawal latency to a radiant heat stimulus is plotted as a function of time after the lesion. **P < 0.01; ***P < 0.001 ipsilateral versus  contralateral (contra) paw. (B ) SNL resulted in significant hyperalgesia to punctate mechanical stimuli in the ipsilateral paw, but mouse genotype did not influence the level of response. The ASIC2 KO and WT mice did not differ in their responses to mechanical stimulation across 5 weeks after the SNL. Both KO and WT animals displayed increased responses to mechanical stimulation after the nerve injury compared with their responses at baseline. The average response to the four von Frey forces is plotted as a function of time after the SNL. *P < 0.05; **P < 0.01 ipsilateral versus  contralateral paw in WT animals; # P < 0.05; ## P < 0.01 ipsilateral versus  contralateral paw in KO mice. (C ) An example of response frequencies to each von Frey stimulus (14 days after the SNL, marked with a rectangle  in B ). ASIC2 WT and KO mice did not differ in their responses to any force applied. See also the figure in Supplemental Digital Content 1, https://links.lww.com/ALN/A608. (D ) SNL resulted in significantly enhanced responses to the mechanical stimulus of stroking in both the ASIC2 KO and WT mice. The average percentage of trials in which the animal responded to stroking of the skin with a von Frey filament is plotted as a function of time after the lesion. ***P < 0.001 significant effect of time by Friedman analysis of variance.