FPR1-, FPRL1- and RAGE-mediated change of cAMP levels in transfected HEK293 cells. For analysis of inhibition of forskolin-stimulated adenylate cyclase activity, FPRL1 (A) and RAGE (B) or ΔRAGE (C); FPR1 (D) and RAGE (E) or ΔRAGE (F); and RAGE (G) or ΔRAGE (H) expressing HEK293 cells were subjected to 25 μM forskolin as well as 1 μM Aβ1–42, 1 μM fMLF, 2.4 μM S100B or 0.75 μM AGE-BSA (AGE) for 15 min at 37°C. cAMP levels were determined as described above (see Methods). The values represent mean ± SEM from four independent experiments. Asterisks indicate a significant difference (*, p < 0.05; **, p < 0,01) between forskolin plus agonists and forskolin alone, as determined by one-way ANOVA followed by the Bonferroni test.