Evaluation of β-AR/cAMP/PKA signaling pathway by ELISA. The NE-dependent stimulation of VEGF, IL-8, and IL-6 protein levels could not be blocked by phentolamine (PHEN) (A). Representative results of VEGF (B), IL-8 (C), and IL-6 (D) protein levels treated with NE, isoproterenol (ISO), dobutamine (DOB), terbutaline (TER), 8-CPT, forskolin (FOR), NE + H89 or NE + PKI for 6 hours. Values are presented as percent of untreated control levels. Each bar represents the mean ± SD. *, P ≤ 0.05; **, P ≤ 0.001.