Fig. 2. Phosphorylation of Glu receptor 1 subunit (GluR1) and its residue (pGluR1 s845) with α-amino-3-hydroxy-5-methyl-4-isoxazoleproprionate–receptor trafficking. (A ) When compared with the vehicle group (Veh), rats that received intrathecal injection with 8-bromo-cyclic adenosine monophosphate (cAMP, 300 μM, 10 μl; test stimulation [TS]+ cAMP) had more GluR1 subunits in the membrane fraction (P2; **P = 0.001 vs. TS + vehicle, n = 4) of the lumbosacral (L6–S2) spinal dorsal horn tissue, whereas total expression level (total) was unaffected. However, cAMP had no effect on the intracellular distribution of Glu receptor 1 subunit (GluR2) in dorsal horn tissue (P = 0.945, n = 4). (B ) Rather than total GluR1 protein level, intrathecal cAMP injection enhanced phophorylation levels of GluR1 s845 spinal dorsal horn neurons (*P = 0.044) when compared with vehicle solution (n = 4). (C , D ) Likewise, intrathecal cAMP produced an increase in the abundance of A kinase–anchoring proteins (AKAP; *P = 0.012) and the RII subunit of protein kinase A (PKA RII; P = 0.030) in membrane fractions as well as a corresponding decrease in the pure cytosolic fraction (S2, *P = 0.0030 and P = 0.005, respectively) when compared with the vehicle group.