Affinity of tamsulosin and its analogs for the cloned ratalpha-1 adrenoceptor subtypes
| Alpha-1A | Alpha-1B | Alpha-1D | |
|---|---|---|---|
| Tamsulosin | 9.97 ± 0.15 | 8.86 ± 0.05**, † | 9.64 ± 0.22 |
| M1 | 9.18 ± 0.07 | 8.13 ± 0.01***, ‡ | 8.83 ± 0.05** |
| M2 | 8.73 ± 0.10 | 7.35 ± 0.05***, ‡ | 8.56 ± 0.12 |
| M3 | 8.62 ± 0.10 | 7.41 ± 0.03***, ‡ | 8.71 ± 0.08 |
| M4 | 9.51 ± 0.05 | 8.58 ± 0.05***, ‡ | 10.21 ± 0.02*** |
| 5-Methylurapidil | 8.45 ± 0.38 | 6.90 ± 0.13***, † | 6.21 ± 0.06*** |
| (+)-Niguldipine | 9.79 ± 0.10 | 7.78 ± 0.02*** | 7.39 ± 0.25*** |
| WB 4101 | 10.67 ± 0.18 | 8.21 ± 0.05***, ‡ | 9.47 ± 0.06*** |
Data are the means ± S.E.M. of three to five experiments and are expressed as −log Ki . ** and ***, P < .01 and .001 vs. alpha-1A adrenoceptors and † and ‡, P < .05 and .001 vs. alpha-1D adrenoceptors in a one-way analysis of variance followed by Tukey-Kramer multiple comparison tests. Data for 5-methylurapidil, (+)-niguldipine and WB 4101 were generated in our laboratory with identical methods and are taken from Michel and Insel (1994), Michel et al. (1996) andChess-Williams et al. (1996) and are shown for reference purposes; in these studies 5-methylurapidil and WB 4101alpha-1A affinities had been generated with the bovine rather than the rat clone.