Fig. 1
CGRP-stimulated cAMP production. CHO cells stably expressing un-tagged (a, c) and CLR-FAP-tagged (b, d) CGRP receptors were treated with increasing concentrations of CGRP, AA58, 8E11 or CGRP8–37 (a, b). cAMP luminescence was measured and displayed as a percent of control (POC). CGRP produced a dose-dependent increase in both un-tagged (EC50 = 8.5 pM, a) and CLR-FAP tagged (EC50 = 8.2 pM, b) CHO cells, whereas AA58, 8E11 and CGRP8–37 demonstrated no agonist activity in either cell line (a, b). Preincubation with AA58, 8E11 or CGRP8–37 inhibited CGRP-induced (20 pM) cAMP production to a similar degree in both un-tagged (IC50 = 0.3, 1.4 and 0.3 nM, respectively, c) and CLR-FAP tagged CHO cells (IC50 = 1.4 nM, 1.9 nM and 3.2 nM, respectively, d)