Effect of modulation of cAMP levels in BMMCs and HMC-1 cells on IL-13 and VEGF secretion. Effects of 10 μM NECA and 100 μM forskolin on IL-13 (A) and VEGF (C) secretion from WT and A2BKO BMMCs. Values are expressed as mean ± SEM of three separate cell preparations. **, p < 0.01, significant difference from basal shown by one-way ANOVA with Dunnett’s posttest. Effects of 10 μM NECA and 100 μM forskolin on IL-13 (B) and VEGF (D) secretion from HMC-1 cells. Values are expressed as mean ± SEM of three experiments. *, p < 0.05 and **, p < 0.01, significant differences from basal determined by one-way ANOVA with Dunnett’s posttest. Effect of adenylate cyclase inhibitor 2′,5′-dideoxyadenosine (ddAdo) on cAMP accumulation (E) in HMC-1 cells stimulated with 10 μM NECA. In the absence of 2′,5′-dideoxyade-nosine, 10 μM NECA increased cAMP levels from 3.2 ± 0.6 to 19.4 ± 2.9 pmol/106 cells. Values are presented as mean percentage ± SEM of NECA-stimulated response in three experiments. F, Effect of 2′,5′-dideoxyadenosine on IL-13 (○) and VEGF (●) secretion from HMC-1 cells stimulated with 10 μM NECA. Values are presented as mean percentage ± SEM of NECA-stimulated response for three experiments.