Radioligand Binding Assay for β1-Adrenoceptor

[³H]-adenine, [³H]-CGP 12177, [¹⁴C]-cAMP, Microscint-20 and Ultima Gold Scintillation fluid were from Perkin Elmer (Coventry, West Midlands, UK). CGP 12177, CGP 20712A, cimaterol and ICI 118551 were from Tocris Bioscience (Bristol, UK). Decyl-β-D-maltopyranoside was from Anatrace (Berkshire, UK). Purified β₁-m23-StaR [8] (link) was provided by Heptares Therapeutics. The following antibodies were used: goat-anti-mouse-Rhodamine secondary antibody (Molecular Probes, Life Technologies, Paisley, UK), horse radish peroxidase-conjugated secondary antibody (Cell Signalling Technology, Leiden, The Netherlands). BODIPY-TMR-CGP (CGP-12177-TMR) was purchased from Molecular Probes (Eugene, OR, USA). Fugene HD transfection reagent and furimazine were from Promega (Southampton, UK). Purified turkey and human ECL2 peptides were obtained from Cambridge Research Biochemicals (Cambridge, UK). All other reagents were from Sigma-Aldrich (Gillingham, UK).