Altered spinal antagonisms of pERK signals induced by Aβ-fiber stimuli in nerve-injured mice. Representative pictures of spinal antagonisms of pERK signals induced by 2000 Hz stimuli (a) and the results of pERK quantification (b).: vehicle (Veh; aCSF), CP-99994 (CP) (10 nmol), MK-801 (MK) (30 nmol), AP-5 (30 nmol), CNQX (10 nmol). *: p < 0.05 vs. sham-vehicle or injury-no stimulus. #: p < 0.05 vs. injury-vehicle. Data represent the means ± S.E.M. from experiments using at least 4 mice. (c) Double-immunostaining images for pERK (green) and the neural marker NeuN (red) after Aβ-fiber stimuli in the spinal cords of nerve-injured mice. Scale bar = 100 μm for (a) and 20 μm for (c).