Validation of expression of the selected genes by qPCR. Saline-treated HA mice vs. desipramine-treated HA mice (A); saline-treated LA mice vs. desipramine-treated LA mice (B). Results are presented as means of relative mRNA levels in 12 individuals per experimental group; error indicators show ± S.E.M. Values differ significantly at *p < 0.05, **p < 0.01 or ***p < 0.001; qPCR values were normalized to geometric mean of the raw expression data of two reference genes: Gapdh and Hprt1. Abbreviations: qPCR, quantitative real-time RT-PCR; HA, high analgesia mice; LA, low analgesia mice; S.E.M., standard error of measurement or mean; Tbp, TATA box binding protein; Hprt1, hypoxanthine phosphoribosyltransferase 1.