Fig. 7

Differential A2AR constitutive activity (CA) in different A2AR heteromers. Constitutive activation of AC in cells expressing A2AR alone or with A2AR plus CB1R, A1R, or D2R. HEK-293T cells were transiently transfected with the cDNA of A2AR alone (3 μg) or with the cDNA of A2AR (1.5 μg) and the cDNA of CB1R, A1R, or D2R (1.5 μg in all cases). CA values are expressed as means ± S.E.M. (n = 5 with quintuplicates in all experiments) of the % of basal values, calculated by dividing the levels of cAMP obtained in each condition by the levels of cAMP in cells transfected with an empty vector (pcDNA3, 3 μg). In addition, the values were normalized by the levels of cell surface expression of A2AR, which was determined by means of SNAP staining (see “Methods”). Statistical analysis was performed by using one-way ANOVA, followed by Tukey’s multiple comparison test (** and ***: p < 0.01 and p < 0.001, respectively, compared with cells only transfected with A2AR)