Table 2.
Binding affinities for α1-AR antagonists at [3H]-silodosin and [3H]-prazosin binding sites in rat tail artery
| Drug | [3H]-silodosin | [3H]-prazosin | pKi low |
|---|---|---|---|
| pKi | pKi high (%high) | ||
| Prazosin | 9.8±0.2 | 9.9±0.1 | |
| Silodosin | 9.9±0.1 | 10.0±0.2 (55±5%) | 7.5±0.2 |
| Tamsulosin | 10.0±0.1 | 9.8±0.2 | |
| BMY 7378 | 6.3±0.2 | 6.4±0.1 | |
| RS-17053 | 8.7±0.3 | 8.8±0.3 (59±4%) | 7.8±0.3 |
| 5-Methylurapidil | 9.0±0.2 | 8.9±0.3 (60±4%) | 7.4±0.2 |
Abbreviations: %high, proportion of high affinity sites; pKi high and pKi low, negative logarithm of the equilibrium constants (pKi) at high and low affinity sites for tested drugs.
Intact tissue segment binding experiments were carried out at 200 pM [3H]-silodosin or 500 pM [3H]-prazosin. Data represent mean±s.e.mean of 4–5 experiments.