Fig. 3.

Cmpd-6 shows no PAM activity on β₁AR-mediated ERK stimulated by a comprehensive panel of ligands. HEK293 cells stably expressing β₁ARs were pretreated with vehicle or 30 μM Cmpd-6 for 20 minutes and then stimulated with serial concentrations of indicated ligands for 5 minutes. A panel of agonists (A–D) and β-blockers (E–G) dose-dependently induced β₁AR-mediated ERK phosphorylation. Cmpd-6 pretreatment showed no effect on these ligands. Data are presented as pERK/total ERK (tERK) ratios normalized to the maximum value in the vehicle group. Data represent the mean ± S.D. for three independent experiments. Dose-response curves and log EC₅₀ values shown in legends were generated with GraphPad Prism. Statistical comparisons were performed using two-way repeated (related)-measures ANOVA with Sidak correction for multiple comparisons and showed no difference between vehicle- and Cmpd-6–treated groups for each ligand. IB, immunoblotting.