Figure 6. cAMP determination in cells coexpressing variable proportions of A_2A and A_2BARs.

(A) Stimulation of cAMP accumulation induced by 100 nM of the A_2B-selective partial agonist BAY60-6583 at HEK-A_2A cells transiently transfected with increasing amounts of cDNA for A_2BAR (0.25–1.5 µg). The basal cAMP level, i.e. HEK-A_2A cells only with medium but without the agonist, was set at 100%. The one-way ANOVA with Dunnett’s post-hoc test showed significant differences. ns: not significant, ^**p < 0.01 (n = 2, in triplicates). (B) Stimulation of cAMP accumulation induced by 100 nM of the A_2A-selective agonist CGS-21680 at HEK-A_2A cells transiently transfected with increasing amounts of cDNA for A_2BAR (0.25–1.5 µg). Basal cAMP, i.e. HEK-A_2A cells only with medium but without the agonist, was set at 100%. The one-way ANOVA with Dunnett’s post-hoc test showed significant differences. ns: not significant, ^*p < 0.05, ^**p < 0.01 (n = 2, in triplicates). (C) Stimulation of cAMP accumulation induced by a combination of 100 nM of the A_2A-selective agonist CGS-21680 and of 100 nM of the A_2B-selective partial agonist BAY60-6583 at HEK-A_2A cells transiently transfected with with increasing amounts of cDNA for A_2BAR (0.25–1.5 µg). Basal cAMP, i.e. HEK-A_2A cells only with medium but without the agonist, was set at 100 %. The one-way ANOVA with Dunnett’s post-hoc test showed significant differences. ns: not significant, ^**p < 0.01 (n = 2, in triplicates).