Table 1.
Bias analysis for the relative effectiveness of endothelin peptides in the human saphenous vein constrictor and ETA-mediated β-arrestin recruitment assays.
| Saphenous vein constrictor assay |
β-Arrestin recruitment assay |
Saphenous vein vs β-arrestin |
||||||
|---|---|---|---|---|---|---|---|---|
| LogR | ΔLogR | RE | LogR | ΔLogR | RE | ΔΔLogR | Bias factor | |
| ET-1 | 8.55 ± 0.15 | 0 ± 0.22 | 1 | 9.46 ± 0.08 | 0 ± 0.11 | 1 | 0 ± 0.24 | 1 |
| ET-2 | 8.26 ± 0.21 | − 0.29 ± 0.26 | 0.51 | 8.67 ± 0.03 | − 0.79 ± 0.08 | 0.16 | 0.49 ± 0.27 | 3.1 |
| ET-3 | 6.80 ± 0.37 | − 1.75 ± 0.40 | 0.018 | 7.11 ± 0.03 | − 2.35 ± 0.08 | 0.0045 | 0.60 ± 0.41 | 4.0 |
| S6b | 8.11 ± 0.12 | − 0.44 ± 0.12 | 0.36 | 8.68 ± 0.06 | − 0.78 ± 0.10 | 0.17 | 0.34 ± 0.15 | 2.2 |
R = (τ / KA), the transducer coefficient, where τ is an index of agonist efficacy and KA is functional affinity of the agonist. ΔLogR is the relative LogR values of test agonists compared to the reference agonist in a particular assay. ΔΔLogR is the relative ΔLogR values for particular agonists between assays. The bias factor is determined as 10ΔΔLogR. Analysis performed as described by van der Westhuizen and colleagues [11].