Effect of beta-AR ligands on human beta-3 AR-mediated activation of ERK and accumulation of cAMP
| Ligand | ERK | cAMP | |||
|---|---|---|---|---|---|
| EC50 | I.A. | Fold/Basal | EC50 | I.A. | |
| nM | nM | ||||
| Isoproterenol | 5 ± 2 | 1 | 2.1 ± 0.3 | 1 ± 1 | 1 |
| Epinephrine | 17 ± 7 | 1.5 | 3.2 ± 0.1 | 121 ± 191-a | 0.81-a |
| Carazolol | 23 ± 7 | 1.2 | 2.7 ± 0.2 | 6 ± 3 | 1.21-b |
| CL 316,243 | 96 ± 7 | 0.8 | 1.8 ± 0.1 | 87 ± 15 | 0.91-b |
| Norepinephrine | 120 ± 4 | 0.9 | 2.0 ± 0.2 | 7 ± 1 | 0.91-b |
| CGP 12177A | 121 ± 20 | 0.8 | 1.8 ± 0.1 | 4 ± 1 | 0.71-b |
| BRL 37344 | Antagonist | 1.2 ± 0.5 | 13 ± 21-b | 1.11-b | |
| Propranolol | Antagonist | 1.0 ± 0.5 | 447 ± 241-a | 0.41-a | |
| Bupranolol | Antagonist | 0.9 ± 0.4 | Antagonist | ||
| Serum | 7.0 ± 1.0 | ||||
Comparison of intrinsic activity (I.A.) and EC50. The I.A. is defined as the maximal effect of a ligand relative to the maximal effect obtained with isoproterenol (I.A. = 1). EC50 values are determined from dose-response curves carried out in the presence of increasing concentrations of agonist ranging from 100 pM to 10 μM (ERK) or 1 pM to 100 μM (cAMP). Results are mean ± S.E.M. of at least three independent experiments performed in duplicate.