Figure 3.

Sustained treatment with betaxolol upregulates levels of the untagged and Renilla luciferase-tagged forms of the CAM β₂-adrenoceptor. (A) HEK293 cells were transfected transiently with cDNAs encoding CAM β₂-adrenoceptor or CAM β₂-adrenoceptor-Renilla luciferase. Twenty-four hours later the cells were exposed to betaxolol (10 μM) (2) or vehicle (1). Twenty-four hours later membranes were prepared and the specific binding of [³H]-DHA (2 nM), measured. (B) HEK293 cells were transfected transiently to express the CAM β₂-adrenoceptor-Renilla luciferase construct. Twenty-four hours later the cells were exposed to betaxolol (10 μM) or vehicle. Twenty-four hours later membranes were prepared and the specific binding of a wide range of [³H]-DHA concentrations measured. Results are representative of three independent experiments. (C) HEK293 cells were transfected transiently to express the CAM β₂-adrenoceptor-Renilla luciferase construct. Twenty-four hours later the cells were exposed to varying concentrations of betaxolol. The specific binding of [³H]-DHA (2 nM) and the luminescence from Renilla luciferase were measured in parallel 24 h later. Data are presented as per cent of maximal effect with results derived from three independent experiments.