title: [Effect of silodosin on intraurethral pressure increase induced by hypogastric nerve stimulation in dogs with benign prostatic hyperplasia].
abstract: 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.
authors.affiliation: Pharmacology Research Laboratory, R&D, Kissei Pharmaceutical Co., Ltd., Azumino City, Japan. yoshitaka-tomiyama@pharm.kissei.co.jp
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Tomiyama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tatemichi
authors.forename: Mariko
authors.initials: M
authors.lastname: Tadachi
authors.forename: Shinya
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Morimichi
authors.initials: M
authors.lastname: Hayashi
authors.forename: Mamoru
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Nobuo
authors.initials: N
authors.lastname: Shibata
mesh_terms: 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
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D007211:Indoles; D009281:Naphthalenes; D010879:Piperazines; D013449:Sulfonamides; C095285:silodosin; D000077409:Tamsulosin; C064357:naftopidil