Fig. 3.

CYM2503 exhibited no affinity for GalR1 and it did not modulate GalR1 signaling. Agonist-induced inhibition of forskolin-stimulated cAMP production in CHO-GalR1 cells was used as an index of GalR1 activation. Forskolin was used at a concentration of 4 μM. (A) Iodine-125 porcine galanin, at 0.1 nM, was not displaced by CYM2503 at up to 100 μM concentration. For comparison, unlabeled rat galanin displaced ¹²⁵I porcine galanin with an IC₅₀ of 5.4 nM in the same experiment. (B) Rat galanin inhibited forskolin-stimulated cAMP accumulation with an IC₅₀ of 7.8 pM in CHO-GalR1 cells, whereas it had no effect in the parent CHO cell line that does not express GalR1. (C) Lack of effect of CYM2503 on cAMP accumulation. CYM2503 at concentrations up to 100 μM had no effect on forskolin-stimulated cAMP production. (D) CYM2503 did not shift the galanin dose–response curve. The data shown here were from one experiment performed in triplicate and are typical of three or four independent experiments that yielded similar results.