(A & B) ASIC3−/− mice do not develop mechanical hyperalgesia in the fatigue-enhanced pain model. (A) Male wild-type mice (n = 7) show significant decreases in muscle withdrawal threshold, while male ASIC3−/− mice (n =8) were significantly different, showing no change in muscle withdrawal threshold from baseline. * P < 0.05. (B) Female wild-type mice (n = 4) show significant decreases in muscle withdrawal threshold, while female ASIC3−/− mice (n = 4) were also significantly different, showing no change in muscle withdrawal from baseline * P < 0.05. (C & D) Antagonism of ASIC3 during the fatigue task prevents the development of mechanical hyperalgesia in the fatigue-enhanced pain model. (C) Male C57BL/6 mice were pretreated with 20µM (n = 14), 70µM (n = 8), or 200µM (n = 7) of the ASIC3 antagonist APETx2 or vehicle (n = 16) during the fatigue task. As a negative control, one group received no treatment (n = 4). Mice treated with 70 µM or 200 µM ApeTx2 had significantly higher post-treatment muscle withdrawal thresholds as compared to the vehicle control. (D) Female C57BL/6 mice were pretreated with either 200 µM APETx2 (n = 4) or vehicle (n = 4) during the fatigue task. Mice treated with APETx2 had significantly higher post-treatment muscle withdrawal thresholds as compared to vehicle control. * P < 0.05.