“…In the first series, the EC 50 of solabegron at human β 1 -, β 2 -, and β 3 -adrenoceptors was 1,259, 3,981, and 3.98 nM, respectively, as compared to 1.0, 0.16, and 3.16 nM, respectively, for isoprenaline, i.e., solabegron was 1,000-and 316-fold selective for β 3 -vs. β 1 -or β 2 -adrenoceptors (Uehling et al 2006); in these experiments, the efficacy of solabegron relative to isoprenaline was 0.79 at β 3 -adrenoceptors but 0.02 and 0.05 at β 1 -or β 2 -adrenoceptors, respectively. In a second series of experiments, solabegron stimulated cyclic AMP accumulation via human β 3 -adrenoceptors with an EC 50 of 6.9 nM as compared to 3.3 nM for isoprenaline, and the efficacy of solabegron relative to isoprenaline was 0.89 (Hicks et al 2007).…”