Figure 7: Expression of GRK phosphorylated-β 2-AR (pβ 2-ARGRK) in splenocytes from arthritic and nonarthritic control rats. (a) Expression of pβ 2-ARGRK in splenocytes was increased in CFA-, SMB-, and MO-challenged rats compared with Saline-treated rats on D21. (b) By D28, pβ 2-AR GRK expression in spleen cells from SMB- and MO-challenged rats was reduced compared with CFA-challenged rats. No difference in pβ 2-ARGRK expression between CFA- and Saline-treated rats was observed. (d) Expression of pβ 2-ARGRK in splenocytes from AA and non-AA rats normalized to β 2-ART levels. MO-treated rats expressed greater pβ 2-ARGRK/β 2-ART levels compared with Saline- and CFA-treated rats on D21 after immune challenge. (e) On D28 after challenge, pβ 2-ARGRK/β 2-ART was significantly increased in CFA-challenged rats compared with all other treatment groups. Splenocytes were harvested, lysed, and proteins resolved by SDS-PAGE. Cellular extracts were probed with an antibody against phosphorylated Ser355/Ser356 of the β 2-AR. (c) Western blot shown is representative of the blots within each treatment group. The data were normalized to β-actin. Data are expressed as a mean pβ 2-ARGRK ± SEM (a)-(b) or mean pβ 2-ARGRK normalized to β 2-ART ± SEM (d)-(e) with an of 8 rats per treatment group. Data were analyzed using one-way ANOVA with Bonferroni posthoc testing (*; **; ***).