Figure 6: Expression of PKA-phosphorylated-β 2-AR (pβ 2-ARPKA) in splenocytes from arthritic and nonarthritic control rats. ((a)–(e)). Expression of pβ 2-ARPKA in splenocytes was reduced in CFA- compared with SMB-, Saline-, and MO-challenged rats D21 (a) and D28 (b) after immune challenge. Expression of pβ 2-ARPKA in splenocytes from AA and non-AA rats at D21 (d) and D28 (e) after immune challenge was normalized to total receptor (β 2-ART) levels. β 2-ARPKA/β 2-ART was reduced in CFA-challenged rats compared with SMB-, MO-, and Saline-treated rats at both time points examined, indicating a disease-specific effect. Spleen cells were harvested, lysed, and total protein collected, then resolved by SDS-PAGE. The data were normalized to β-actin. Cellular extracts were probed with an antibody against phosphorylated Ser345, Ser346 of the β 2-AR and quantified by densitometry. An example of the western blots at D21 is shown in (c). Each bar represents the mean optical density ± SEM (a)-(b) or mean pβ 2-ARPKA 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 (*; **; ***).