摘要
Tamsulosin (10-10-10-9 M) or prazosin (10-9-10-8 M) concentration dependently blocked the tension responses to electrical field stimulation (0.3 ms duration, 80 V and 20 Hz) in human hyperplastic prostate with IC50 values of (1.93 ± 0.26) x 10-10 M and (2.11 ± 0.21) x 10-9 M, respectively. The relative potency of tamulosin with reference to prazosin was 10.96. The pA2 values for tamulosin and prazosin against phenylephrine-induced contractions were 10.05 ± 0.16 and 9.25 ± 0.07, respectively. The relative potency of tamsulosin with reference to prazosin was 6.31. In the presence of prazosin to block α1-adrenoceptor-mediated responses, nifedipine (10-5 M), but not tamsulosin (10-9 M), significantly blocked the tension responses in human hyperplastic prostate induced by increasing [Ca2+](o) concentrations (10-4 to 3 x 10-3 M) in a Ca2+-free environment pre-depolarized with 60 mM K+. Additionally, the effects of prazosin and tamsulosin on electrical field stimulation-evoked [3H]noradrenaline release were studied on the S3/S2 ratios. It appeared that both drugs had little effect on this release reaction, with S3/S2 ratios of 0.96 ± 0.02 and 0.90 ± 0.02, respectively. These results indicate that tamsulosin is a potent antagonist against endogenous sympathetic stimulation in human hyperplastic prostate.
| 原文 | 英語 |
|---|---|
| 頁（從 - 到） | 177-180 |
| 頁數 | 4 |
| 期刊 | European Journal of Pharmacology |
| 卷 | 305 |
| 發行號 | 1-3 |
| DOIs | |
| 出版狀態 | 已出版 - 03 06 1996 |
| 對外發佈 | 是 |