Table 3.
Functional affinities for various α1-adrenoceptor antagonists estimated in contractile responses to noradrenaline in rabbit iris dilator
|
Pigmented rabbit |
Albino rabbit |
|
|---|---|---|
| pKB (slope) | pKB (slope) | |
| Prazosin | 6.7 ± 0.1 (0.99) | 7.8 ± 0.2 (0.86) |
| Bunazosin | 7.0 ± 0.1 (1.11) | 7.7 ± 0.2 (1.16) |
| RS-17053 | <6 | 6.3 ± 0.2a |
| Silodosin | 9.0 ± 0.2 (1.04) | 9.5 ± 0.2 (1.17) |
| Tamsulosin | 9.2 ± 0.1 (1.09) | 9.7 ± 0.1 (0.97) |
| 5-Methylurapidil | 6.8 ± 0.2 (1.17) | 7.6 ± 0.2 (1.01) |
| BMY 7378 | <6 | <6 |
Data shown are means ± SEM from four or six experiments. Slope was calculated from Schild analysis, which was not significantly different from unity.
a
Estimated at 1 µmol·L−1 RS-17053 by the concentration-ratio method (Furchgott, 1972).
BMY 7378, 8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4,5]decane-7,9-dione dihydrochloride; SEM, standard error of the mean; RS-17053, N-[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro-α,α-dimethyl-1H-indole-3-ethamine hydrochloride.