Regulation of RGS4, Tra2β and SRp20 levels in rat LC after acute and chronic morphine administration.

(A) Representative IHC images of Tra2β and RGS4 in rat LC slices after acute saline, morphine and naloxone+morphine administration. Scale bars: 80 µm. (B) Quantitative analysis of Tra2β (acute saline, 1.00±0.01; acute morphine, 0.83±0.02; naloxone+morphine, 0.95±0.06), RGS4 (acute saline, 1.00±0.02; acute morphine, 0.76±0.03; naloxone+morphine, 0.93±0.07) and SRp20 (acute saline, 1.00±0.08; acute morphine, 1.01±0.07; naloxone+morphine, 1.03±0.02) positive cell number per cubic millimeter in rat LC slices. (C–D) Representative immunoblot images (C) and data statistics (D) showing the relative protein level (%GAPDH) of Tra2β, RGS4 and SRp20 in rat LC after acute morphine administration, normalized to that of acute saline group (Tra2β, 0.57±0.06; RGS4, 0.64±0.02; SRp20, 0.93±0.07; *p<0.05, **p<0.01, ***p<0.001, compared to saline group, using paired t-tests). (E) Representative IHC images of Tra2β and RGS4 in rat LC slices after chronic saline, chronic morphine and naloxone following chronic morphine administration. Scale bars: 80 µm. (F) Quantitative analysis of Tra2β (chronic saline, 1.00±0.01; chronic morphine, 1.24±0.06; chronic morphine+naloxone, 0.98±0.04), RGS4 (chronic saline, 1.00±0.03; chronic morphine, 1.23±0.03; chronic morphine+naloxone, 0.99±0.04) and SRp20 (chronic saline, 1.00±0.01; chronic morphine, 1.02±0.01; chronic morphine+naloxone, 0.98±0.07) positive cell number per cubic millimeter in rat LC slices. (G–H) Representative immunoblot images (G) and data statistics (H) showing the relative protein level (%GAPDH) of Tra2β, RGS4 and SRp20 in rat LC after chronic morphine and naloxone following chronic morphine administration, normalized to that of chronic saline group (Tra2β, chronic morphine, 1.27±0.02, chronic morphine+naloxone, 0.92±0.02; RGS4, chronic morphine, 1.45±0.06, chronic morphine+naloxone, 0.75±0.04; SRp20, chronic morphine, 1.06±0.03, chronic morphine+naloxone, 0.95±0.06; *p<0.05, **p<0.01, ***p<0.001, using paired t-tests). The molecular weight of Tra2β, RGS4, SRp20 and GAPDH are 40 kDa, 28 kDa, 20 kDa and 38 kDa, respectively. Data are expressed as mean ± s.e.m. from at least three independent experiments; “n” as denoted inside bar graphs, represents the number of rats. *p<0.05, **p<0.01, ***p<0.001, using one-way ANOVA followed by Tukey’s multiple-comparison test, unless otherwise specified.