Figure 2.
G-protein αs, adenylyl cyclase, and Epac, but not PKA, are involved in PKCϵ translocation. A, DRG cultures were pretreated for 15 min with indicated concentrations [1, 10, 100, and 1000× the CMIQ-IC50 (0.03-30 μm)] of the PKA-specific inhibitor CMIQ (Lu et al., 1996) before stimulation with 1 μm isoproterenol for 30 s. Cultures not treated with either CMIQ or isoproterenol served as negative controls. B, Injection of the PKA inhibitor CMIQ (2.5 μg/2.5 μl) intradermally in rat paws did not change the mechanical paw-withdrawal threshold. Injection of active PKA [PKA catalytic subunit (PKAcs); 25 U/2.5 μl] induced robust mechanical hyperalgesia. Preinjection of CMIQ 15 min before the injection of PKAcs completely blocked the PKA-induced hyperalgesia in vivo. C, Cultures were stimulated with activators of G-protein αs (cholera toxin; 1 μg/ml), adenylyl cyclase (forskolin, 5 μm), and Epac (CPTOMe, 10 μm), for the indicated time. Unstimulated cells served as a negative control, and isoproterenol (1 μm, 30 s)-treated cells served as a positive control. *p < 0.05; **p < 0.01. Error bars represent SEM.