title: Effect of detrusor overactivity on the expression of aquaporins and nitric oxide synthase in rat urinary bladder following bladder outlet obstruction.
abstract: BACKGROUND
  Aquaporins (AQPs) have recently been reported to be expressed in rat and human urothelium. Nitric oxide (NO) is thought to play a role in the bladder overactivity related to bladder outlet obstruction (BOO). The purpose of this study is to investigate the effect of BOO on the expression of AQP2-3 and nitric oxide synthase (NOS) isoforms in rat urothelium.
  
  
  METHODS
  Female Sprague-Dawley rats (230-240 g, n = 60) were divided into 2 groups. The control group (n = 30) and the partial bladder outlet obstruction (BOO) group (n = 30). After 4 weeks, we performed a urodynamic study to measure the contraction interval and contraction pressure. The expression and cellular localization of AQP2-3, endothelial nitric oxide synthase (eNOS) and neuronal nitric oxide synthase (nNOS) were determined by Western blot and immunohistochemistry.
  
  
  RESULTS
  On the cystometrogram, the estimated contraction interval time (minutes, mean ± SE) was significantly lower in the BOO group (3.0 ± 0.9) than in the control group (6.3 ± 0.4; p < 0.05). AQP2 was localized in the cytoplasm of the epithelium, whereas AQP3 was found only in the cell membrane of the epithelium. The protein expression of AQP2-3, eNOS and nNOS was significantly increased in the BOO group.
  
  
  CONCLUSIONS
  Detrusor overactivity induced by BOO causes a significant increase in the expression of AQP2-3, eNOS, and nNOS in rat urinary bladder. This may imply that the AQPs and NOS isoforms have a functional role in the bladder dysfunction that occurs in association with BOO.
authors.affiliation: Department of Urology, Chonnam National University Medical School, Gwangju, Korea;
authors.forename: Sun-Ouck
authors.initials: SO
authors.lastname: Kim
authors.forename: Dongjune
authors.initials: D
authors.lastname: Choi
authors.forename: Seung Hee
authors.initials: SH
authors.lastname: Song
authors.forename: Kyu Youn
authors.initials: KY
authors.lastname: Ahn
authors.forename: Dongdeuk
authors.initials: D
authors.lastname: Kwon
authors.forename: Kwangsung
authors.initials: K
authors.lastname: Park
authors.forename: Soo Bang
authors.initials: SB
authors.lastname: Ryu