title: In vitro evaluation of ureteral contractility: a comparative assessment of human, porcine and sheep ureteral response to vardenafil.
abstract: OBJECTIVE
  Basic science studies of ureteral physiology and pathophysiology are commonly performed on animal ureters due to several limitations associated with human ureteral sampling. In this work we question whether animal ureters are good replicas of human ureteral behavior for pharmacological studies.
  
  
  METHODS
  Ureteral rings from human, porcine and ovine ureters underwent the same organ bath protocol. After stimulation with KCl, ureters were subjected to different doses of vardenafil. Basic contractility and ureteral response to vardenafil were analyzed.
  
  
  RESULTS
  A different pattern of basic contractility was evidenced between species. Vardenafil administration induced a dose-dependent reduction in KCl-induced amplitude increase in human ureters and a dose-dependent reduction in autonomic contractile rhythm of porcine and ovine ureters. Although animal ureters could predict the relaxant response of human samples to vardenafil, its effect would have been overestimated using only animal models.
  
  
  CONCLUSIONS
  Human ureteral investigations cannot entirely be replaced by existing animal models since results of the latter will vary significantly according to the tested pharmaceutical agent.
authors.affiliation: Department of Urology, University of Patras, Patras, Greece.
authors.forename: Iason
authors.initials: I
authors.lastname: Kyriazis
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Kallidonis
authors.forename: Ioannis
authors.initials: I
authors.lastname: Georgiopoulos
authors.forename: Abdulrahman
authors.initials: A
authors.lastname: Al-Aown
authors.forename: George
authors.initials: G
authors.lastname: Sakellaropoulos
authors.forename: Jens-Uwe
authors.initials: JU
authors.lastname: Stolzenburg
authors.forename: Evangelos
authors.initials: E
authors.lastname: Liatsikos
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D058986:Phosphodiesterase 5 Inhibitors / Q000494:pharmacology*; D012756:Sheep; D013552:Swine; D014513:Ureter / Q000187:drug effects* / Q000502:physiology; D000069058:Vardenafil Dihydrochloride / Q000494:pharmacology*
chemical_list: D058986:Phosphodiesterase 5 Inhibitors; D000069058:Vardenafil Dihydrochloride