Fig. 6.
Effect of a locally applied combination of the mixed glucocorticoid receptor/mineralocorticoid receptor agonist 6-α methylprednisolone and mineralocorticoid receptor antagonist eplerenone (“METH-P + EPL”) on pain behaviors and on sensory neuron excitability measured on postoperative day (POD) 3. The combined drugs significantly reduced the mechanical hypersensitivity induced by local dorsal root ganglion inflammation (LID) at all time points (A; paw withdrawal threshold [PWT]) and reduced responses to light brush strokes and acetone (B, C) at the indicated times. **P < 0.01; ***P < 0.001, significant difference between the two groups on the indicated day (two-way repeated-measures ANOVA with Bonferroni post-test). N = 6 rats per group. In cells that were recorded in isolated whole dorsal root ganglia, 3 days after inflammation, spontaneous activity (SA) was increased by LID and decreased by 6-α methylprednisolone plus eplerenone (D). Rheobase was not significantly affected by the steroid treatment (E). Threshold was significantly lower in the steroid-treated group only (F). N = 86 cells from five rats in LID + METH-P + EPL POD3 group. Data from normal and LID POD3 cells replotted from previous figure for comparison. **P < 0.01; ***P < 0.001, significant difference between normal and LID groups; #P < 0.05; ##P < 0.01; significant difference between LID and LID+ METH-P + EPL group (one-way ANOVA with Bonferroni post-test or Kruskal–Wallis test with Dunn multiple comparison post-test).