FIGURE 2.

cAMP signaling in HEK293 cells expressing single receptors or CB₂R-GPR55 heteromers. cAMP production in HEK-CB₂ (A–C), HEK-GPR55 (D and E), or HEK-CB₂-GPR55 cells (F and G) treated (A and F) or not treated (B–E and G) overnight with 10 ng/ml PTX or with 100 ng/ml CTX. Cells were preincubated with vehicle or with the antagonists AM630 or HBA and stimulated with increasing concentrations of HU-308 or LPI in the absence or presence of 0.5 μm FK. Values are mean ± S.E. of n = 4–7 and are expressed as a percentage of the FK-treated cells in each condition. One-way ANOVA followed by Bonferroni post hoc test showed a significant effect over vehicle-treated cells (*, p < 0.05; **, p < 0.01; ***, p < 0.001) or over the FK effect (##, p < 0.01; ###, p < 0.001).