Fig. 4

Chronic oxycodone exposure modulates translation in rat nucleus accumbens area. a Upper panels Real-time-PCR analysis of actin, ATF4, and PDGFRα mRNAs distribution in sucrose density gradients. Nucleus accumbens lysates were ultracentrifuged and fractionated similar to that shown on Fig. 3b. Filled triangle, water; Filled circle, oxycodone samples. Graphs represent percentage of individual mRNA in each fraction. Lower panel graphs representing percentage of individual mRNA in polysomal complexes (fractions #7–12) relative to the amount of this mRNA in all twelve fractions. The graphs represent the mean value from three independent polysomal ultracentrifugations (±SEM). Actin, p = 0.95; ATF4, p < 0.05; PDGFRα, p < 0.001. Open bars water samples; gray filled bars oxycodone samples. b Immunohistochemical analysis of actin, ATF4, PDGFRα, and phosphorylated eIF2α staining in nucleus accumbens areas. Left representative images. Scale bar denotes 20 μm. Right statistical analysis of the data. Open bars water samples; gray filled bars oxycodone samples. The intensity of actin stating was analyzed using “Density” method, and the intensity of ATF4, PDGFRα, and phospho-eIF2α staining was analyzed using MeanQ method. The graphs represent the mean value of intensities measured in brain slides obtained from three animals for each treatment (±SEM). In each slide, at least 3 fields containing 13–74 cells each were investigated. Statistical analysis was performed using Student’s t test. Actin, p = 0.93; ATF4, p < 0.001; PDGFRα, p < 0.001; P-eIF2α, p < 0.01