Validation of microarray data by RT-qPCR. Correlation between microarray (x-axis) and RT-qPCR (y-axis) data. This correlation was analyzed by Spearman’s rho test and a high statistical significance [r (12) = 0.884, p < 0.001] was observed. Values used in this graph were taken from results presented in Table 4. Each gene is labeled with a symbol and up- and down-regulated genes are marked in red and green, respectively: ♦, grb2 and dao.1; ●, magi1b and copb2; ▲, bnip4 and otpb; x, camk1gb and sox19b; Ӿ, acox1 and wls; +, grik-l; −, plg. In the case of two regulated genes (bnip4 and grb2) after chronic morphine exposure that are represented by two probe sets each one, we have included in this figure the highest microarray data: Dr. 24320.1, bnip4 + 2.36 FC (▲), and Dr. 7717.2, grb2, +2.02 FC (♦).