ab118167 ligand binding and displacement. Top (A,C): ab118167 ligand (100 nm) binding to two different live cell lines expressing β1 (A) or β2 (C) adrenoceptors. Bottom (B, D): Binding blocked in the same cell lines β1 (B) or β2 (D) by the unlabelled competitor ICI118551 (1 µM). Nuclei have been counter-stained with Hoechst.