Figure 1

Pharmacological plasticity in the spinal antagonism of Aβ-, Aδ-, and C-fiber stimulation-mediated nociceptive behaviors in nerve-injured mice. The threshold represents the minimum intensity (μA) required to produce a paw withdrawal response to electrical stimulation with 2000 Hz (Aβ-fiber) (a, d), 250 Hz (Aδ-fiber) (b, e), and 5 Hz (C-fiber) (c, f). Vehicle or drugs were administrated intrathecally to naïve (a-c) or nerve-injured mice (d-f), 10 min prior to the electrical stimulation. Vehicle (Veh; aCSF or 3.3% DMSO), CP-99994 (CP), MK-801 (MK). *: p < 0.05 vs. vehicle (aCSF or 3.3% DMSO in a-c) or sham operation (d-f). #: p < 0.05 vs. injury-vehicle. Data represent the means ± S.E.M. from experiments using at least 6 mice.