Table 2.
Functional affinities for various α1-adrenoceptor antagonists estimated in contractile responses to noradrenaline in rabbit prostate
| Drug | pKB | Slope (Schild analysis) |
|---|---|---|
| Prazosin | 7.6±0.2 | 1.15 |
| Bunazosin | 7.9±0.2 | 1.03 |
| Silodosin | 9.6±0.1a | |
| Tamsulosin | 9.6±0.1a | |
| RS-17053 | 6.7±0.3a | |
| 5-Methylurapidil | 8.0±0.1 | 0.94 |
| BMY-7378 | NI |
Mean±s.e. from four or five experiments.
NI: no inhibition at 1 μM BMY-7378.
a
Estimated at 3 nM silodosin or tamsulosin and 1 μM RS-17053 by the concentration ratio method (Furchgott, 1972).