title: The relaxant effect of ginseng saponin on the bladder and prostatic urethra: an in vitro and in vivo study.
abstract: OBJECTIVE
  To assess the effects of ginseng saponin on relaxation of the bladder and prostatic urethra and to determine its mechanism of action.
  
  
  METHODS
  For the in vitro study, prostatic urethra muscle strips were harvested from 18 male New Zealand rabbits. The strips were mounted in organ baths and connected to force displacement transducers. After stabilization, maximal tissue contractions were obtained by the application of phenylepinephrine to the urethra strips, and a dose-response curve for ginseng saponin was constructed (10(-6)-10(-2)M). After pretreatment of urethra strips with N-nitro-L-arginine methyl ester (L-NAME), another dose-response curve for ginseng saponin was constructed. For the in vivo study, we used adult male Sprague-Dawley rats divided into three groups [control, partial bladder outlet obstruction (PBOO) and saponin-fed groups], and we monitored the vesical pressure (P(ves)) and urethral perfusion pressure (UPP).
  
  
  RESULTS
  The ginseng saponin induced a significant dose-dependent relaxant effect on the prostatic urethra strips. A significant relaxant effect of ginseng saponin was observed from 10(-3)M, and ginseng saponin significantly relaxed urethra strips by 50.2 ± 20.26% at 10(-2)M. The relaxant effect was partially inhibited with L-NAME pretreatment. In the in vivo study, the change in UPP between baseline and relaxation was significantly higher in the saponin group than in the control or PBOO group (p < 0.001). The saponin group showed a significantly lower baseline P(ves) than the PBOO group.
  
  
  CONCLUSIONS
  We observed a significant relaxation effect of ginseng saponin on the bladder and prostatic urethra in both in vitro and in vivo studies. The mechanism by which ginseng saponin induces relaxation appears to involve the nitric oxide/nitric oxide synthase pathway.
authors.affiliation: Department of Urology, Korea University Hospital, Seoul, Republic of Korea.
authors.forename: H A
authors.initials: HA
authors.lastname: Jang
authors.forename: S
authors.initials: S
authors.lastname: Cho
authors.forename: S G
authors.initials: SG
authors.lastname: Kang
authors.forename: Y H
authors.initials: YH
authors.lastname: Ko
authors.forename: S H
authors.initials: SH
authors.lastname: Kang
authors.forename: J H
authors.initials: JH
authors.lastname: Bae
authors.forename: J
authors.initials: J
authors.lastname: Cheon
authors.forename: J J
authors.initials: JJ
authors.lastname: Kim
authors.forename: J G
authors.initials: JG
authors.lastname: Lee
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D005894:Panax / Q000737:chemistry; D010656:Phenylephrine / Q000494:pharmacology; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018517:Plant Roots; D011312:Pressure; D011470:Prostatic Hyperplasia / Q000150:complications / Q000378:metabolism / Q000503:physiopathology; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D012503:Saponins / Q000302:isolation & purification / Q000494:pharmacology*; D014521:Urethra / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D001743:Urinary Bladder / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D001748:Urinary Bladder Neck Obstruction / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D014563:Urodynamics / Q000187:drug effects
chemical_list: D004791:Enzyme Inhibitors; D010936:Plant Extracts; D012503:Saponins; D010656:Phenylephrine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester