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

<p>(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; *<i>p</i><0.05, **<i>p</i><0.01, ***<i>p</i><0.001, compared to saline group, using paired <i>t</i>-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; *<i>p</i><0.05, **<i>p</i><0.01, ***<i>p</i><0.001, using paired <i>t</i>-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; “<i>n</i>” as denoted inside bar graphs, represents the number of rats. *<i>p</i><0.05, **<i>p</i><0.01, ***<i>p</i><0.001, using one-way ANOVA followed by Tukey’s multiple-comparison test, unless otherwise specified.