title: Suppression of detrusor overactivity in rats with bladder outlet obstruction by a type 4 phosphodiesterase inhibitor.
abstract: OBJECTIVE
  To investigate the effects of a selective type 4 cyclic nucleotide phosphodiesterase (PDE4) inhibitor, IC486051, on bladder activity in normal rats and those with and bladder outlet obstruction (BOO), as inhibition of PDE4 leads to elevation of intracellular cAMP levels and relaxation of smooth muscle.
  
  
  METHODS
  BOO was induced in female Sprague-Dawley rats by tying a silk ligature around the urethra. At 4 or 6 weeks after inducing BOO, conscious rats were assessed by cystometry with the urethral ligature intact. In unobstructed rats, blood pressure was also measured.
  
  
  RESULTS
  In unobstructed rats, IC486051 (0.1 mg/kg intravenously) produced no significant changes in cystometric variables, while at a dose of 0.5 mg/kg maximum voiding pressure was reduced by 34%. At both doses, there was a small, transient increase in blood pressure. In both 4- and 6-week BOO rats IC486051 dose-dependently decreased the number and amplitude of non-voiding bladder contractions by up to 80%, relative to pre-treatment values. At doses of 0.1 and 0.5 mg/kg IC486051 had no significant effect on voiding variables. In the 4-week BOO rats, a dose of 1.0 mg/kg decreased bladder capacity, voided volume and residual volume by 21%, 32% and 18%, respectively. In 6-week BOO rats, a dose of 1.0 mg/kg decreased maximal voiding pressure by 17% and pressure threshold for voiding by 28%. In both groups of rats with BOO, voiding efficiency was unchanged.
  
  
  CONCLUSIONS
  A selective PDE4 inhibitor can effectively suppress detrusor overactivity in rats with BOO, at doses that have no effect on voiding bladder contractions. Thus, selective PDE4 inhibitors should be considered for the treatment of overactive bladder in patients with BOO.
authors.affiliation: Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Nishiguchi
authors.forename: Dong Deuk
authors.initials: DD
authors.lastname: Kwon
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kaiho
authors.forename: Michael B
authors.initials: MB
authors.lastname: Chancellor
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kumon
authors.forename: Peter B
authors.initials: PB
authors.lastname: Snyder
authors.forename: Naoki
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000818:Animals; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D005260:Female; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D001748:Urinary Bladder Neck Obstruction / Q000150:complications*; D053201:Urinary Bladder, Overactive / Q000150:complications / Q000188:drug therapy* / Q000201:enzymology
chemical_list: D010726:Phosphodiesterase Inhibitors; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4