Fig. 4.

Conditioned responses (as a percentage of the baseline) in early- and late-phase monoiodoacetate (MIA) animals. A: in early-phase MIA animals, the spinal application of atipamezole completely abolished DNIC-induced neuronal inhibition, whereas the spinal application of SB-269970 only partially reversed it (atipamezole, n = 5; SB-269970, n = 6). B: in late-phase MIA animals, both the subcutaneous injection of tapentadol and the spinal application of AS-19 significantly restored neuronal inhibition to levels comparable to that observed in sham controls (tapentadol, n = 6; AS-19, n = 6). *P < 0.05; **P < 0.01; ^P < 0.05; ^^P < 0.01; Kruskal-Wallis.