[Effect of silodosin on intraurethral pressure increase induced by hypogastric nerve stimulation in dogs with benign prostatic hyperplasia].
We compared the urethral and cardiovascular effects of silodosin (selective alpha(1A)-adrenoceptor antagonist), a novel medication for benign prostatic hyperplasia (BPH), with those of tamsulosin (selective alpha(1A)/alpha(1D)-adrenoceptor antagonist) and naftopidil (selective alpha(1D)-adrenoceptor antagonist). We evaluated the effects of these three drugs on the increase in intraurethral pressure (IUP) induced by electrical stimulation of the hypogastric nerve in anesthetized dogs with spontaneous BPH. All three drugs dose-dependently reduced both the increase in IUP and the mean blood pressure (MBP). The rank order of potencies was tamsulosin>silodosin>naftopidil for the reductions in both IUP and MBP. However, the uroselectivity (ED(15) value for hypotensive effect/ID(50) value for reduction in IUP) of silodosin (uroselectivity, 19.8) was about 21 and 4 times higher than that of tamsulosin (0.939) and naftopidil (4.94), respectively. These data suggest that silodosin might be one of the most useful medications for dysuria in BPH patients.
Tomiyama
Yoshitaka
Y
Pharmacology Research Laboratory, R&D, Kissei Pharmaceutical Co., Ltd., Azumino City, Japan. yoshitaka-tomiyama@pharm.kissei.co.jp
Tatemichi
Satoshi
S
Tadachi
Mariko
M
Kobayashi
Shinya
S
Hayashi
Morimichi
M
Kobayashi
Mamoru
M
Yamazaki
Yoshinobu
Y
Shibata
Nobuo
N
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D007001:Hypogastric Plexus / Q000502:physiology*; D007211:Indoles / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D009281:Naphthalenes / Q000494:pharmacology / Q000627:therapeutic use; D010879:Piperazines / Q000494:pharmacology / Q000627:therapeutic use; D011312:Pressure; D011467:Prostate / Q000187:drug effects / Q000473:pathology; D011470:Prostatic Hyperplasia / Q000188:drug therapy / Q000503:physiopathology*; D013449:Sulfonamides / Q000494:pharmacology / Q000627:therapeutic use; D000077409:Tamsulosin; D014521:Urethra / Q000187:drug effects* / Q000503:physiopathology
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D007211:Indoles; D009281:Naphthalenes; D010879:Piperazines; D013449:Sulfonamides; C095285:silodosin; D000077409:Tamsulosin; C064357:naftopidil