Fig. 9.  AKAP mediates PKA-dependent cross-organ sensitization of the urethra reflex. (A ) Total RNA extracted form the lumbosacral dorsal horn tissue obtained from control (conAKAP) and siAKAP animals, as well as transcription of gene encoding AKAP, were assessed using real-time reverse transcription polymerase chain reaction with AKAP-specific cloning primers. Expression of AKAP messenger RNA in siAKAP rats was significantly lower than that in control animals (**P < 0.001, n = 4). Immunoblotting demonstrated that, when compared with controls, small interfering RNA directly knocked-down the expression level of AKAP (*P = 0.015, n = 7). (B ) Reflex sensitization caused by intracolonic 8-methyl-N -vanillyl-trans -6-nonenamide (0.1 ml capsaicin, 0.1% [Cap]; 192.3 ± 42.1 spikes/stimulation, **P < 0.001 versus  test stimulation [TS]+ vehicle in controls) in siAKAP animals was remarkably attenuated (# P < 0.001, n = 7) even though capsaicin concentration was increased to 0.3%. (C ) Correlated up-regulation of phosphorylated Glu receptor 1 subunit serine 845 residue (pGluR1 s845) in total lysate (**P = 0.002 vs.  TS + vehicle, n = 4) as well as GluR1 and AKAP in the membrane fractions (P2; n = 4) caused by capsaicin instillation was remarkably attenuated in the siAKAP group when compared with controls (## P = 0.004 in GluR1, P = 0.020 in pGluR1 and ## P = 0.003 in AKAP vs.  TS + vehicle, n = 4). AKAP = PKA-A kinase–anchoring protein; EUSE = external urethra sphincter electromyogram; PKA = protein kinase A; sec = seconds; siAKAP = suppressed AKAP expression using specific small interfering RNA; uV =μvolts.