[125I]-Iodocyanopindolol Binding.

HEK293 cells stably expressing a FLAG–β₂AR were isolated and washed three times with assay buffer (HBSS with calcium and magnesium, 0.1% BSA, pH 7.4), diluted to 25,000 cells per milliliter, and incubated with 1 nM [¹²⁵I]-iodocyanopindolol in the presence or absence of pepducin or carvedilol for 2 h at 25 °C. Incubations were terminated by rapid filtration on GF/B filters. Filters were washed four times with 5 mL of cold assay buffer and [¹²⁵I]-iodocyanopindolol binding was quantitated by γ-emission counting.