Fig. 3.  Mean (percentage of control) ± SEM quantification of α²δ-1, 5HT3A, and μ-opioid receptor-1 mRNA concentrations in morphine- and saline-treated animal dorsal root ganglia (both groups, n = 8) on postoperative days 7–10 normalized to the mean of the saline group for the corresponding three measures (messenger ribonucleic acid [mRNA] concentration = 100%). There was no significant difference between groups (P > 0.05).