Table 3.
Affinity estimates of antagonists on the circular smooth muscle of the pig internal anal sphincter.
| Antagonist |
Affinity at published α1-adrenoceptor subtypes |
Affinity at pig internal anal sphincter with |
|||
|---|---|---|---|---|---|
| Phenylephrine | Noradrenaline | ||||
| α1A | α1B | α1D | Mean pKB | Mean pKB | |
| BMY7378 | 6.5±0.2 | 6.9±0.2 | 8.9±0.5 | 6.59±0.15 | 6.33±0.13 |
| 5-MU | 8.8±0.1 | 7.2±0.1 | 7.9±0.1 | 8.51±0.10 | 8.31±0.10 |
| Prazosin | 9.3±0.2 | 9.6±0.1 | 9.6±0.1 | 8.58±0.10 | 8.15±0.08 |
| RS100329 | 9.6±0.1 | 7.8±0.2 | 7.9±0.1 | 9.01±0.14 | 9.06±0.22 |
| RS17053 | 9.4±0.1 | 7.6±0.3 | 7.4±0.3 | <7.0 | <7.0 |
Published affinity ranges from functional and binding studies (Michel and Insel, 1994; Burt et al., 1995; Goetz et al., 1995; Kenny et al., 1995; Buckner et al., 1996; Marshall et al., 1996; Ford et al., 1997; Noble et al., 1997; Langer, 1999; Williams et al., 1999; Mackenzie et al., 2000).