Table II.
Ligands (Ki) μM (95% confidence intervals) |
||||
---|---|---|---|---|
Receptor | Norepinephrine | Epinephrine | Isoproterenol | Albuterol (salbutamol) |
Wild-type | 84 (49–144) | 4.9 (3.5–7.0) | 4.2 (2.4–7.5) | 25 (21–30) |
V114I | 167 (52–535) | 33 (16–68) | 6.6 (3.1–14) | 11 (4.1–31) |
V114L | 2014 (722–5613) | 486 (241–978) | 92 (48–177) | 82 (42–160) |
V114C | 960 (434–2123) | 312 (169–572) | 57 (35 to 93) | 101 (57–176) |
V114Eb | 752 (164–3437) | 2725 (1277–5813) | 1400 (590–3320) | 2129 (954–4748) |
The binding of unlabelled agonists to wild-type β2-AR and mutant receptors was determined by competition with 3 nM [3H] dihydroalprenolol as the radioligand (TRK 649, GE Health care). Data obtained from determinations of three independent transfections and analyzed by nonlinear regression as described under Material and Methods section.
High nonspecific binding of 15–20% observed.