title: Water avoidance stress induces frequency through cyclooxygenase-2 expression: a bladder rat model.
abstract: OBJECTIVE
  Water avoidance stress is a potent psychological stressor and it is associated with visceral hyperalgesia, which shows degeneration of the urothelial layer mimicking interstitial cystitis. Cyclooxygenase-2 inhibitors have been recognized to ameliorate frequency both in clinical and experimental settings. We investigated the voiding pattern and cyclooxygenase-2 expression in a rat bladder model of water avoidance stress.
  
  
  METHODS
  After being subjected to water avoidance stress or a sham procedure, rats underwent metabolic cage analysis and cystometrography. Real time reverse transcription polymerase chain reaction was carried out to examine cyclooxygenase-2 messenger ribonucleic acid in bladders of rats. Protein expression of cyclooxygenase-2 was analyzed with immunohistochemistry and western blotting. Furthermore, the effects of the cyclooxygenase-2 inhibitor, etodolac, were investigated by carrying out cystometrography, immunohistochemistry and western blotting.
  
  
  RESULTS
  Metabolic cage analysis and cystometrography showed significantly shorter intervals and less volume of voiding in water avoidance stress rats. Significantly higher expression of cyclooxygenase-2 messenger ribonucleic acid was verified by reverse transcription polymerase chain reaction. Immunohistochemistry and western blotting showed significantly higher cyclooxygenase-2 protein levels in water avoidance stress bladders. Furthermore, immunohistochemistry showed high cyclooxygenase-2 expression exclusively in smooth muscle cells. All water avoidance stress-induced changes were reduced by cyclooxygenase-2 inhibitor pretreatment.
  
  
  CONCLUSIONS
  Chronic stress might cause frequency through cyclooxygenase-2 gene upregulation in bladder smooth muscle cells. Further study of cyclooxygenase-2 in the water avoidance stress bladder might provide novel therapeutic modalities for interstitial cystitis.
authors.affiliation: Department of Urology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Takao
authors.forename: Jiro
authors.initials: J
authors.lastname: Nakayama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kiuchi
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Okuda
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Fukuhara
authors.forename: Iwao
authors.initials: I
authors.lastname: Yoshioka
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Matsuoka
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyagawa
authors.forename: Akira
authors.initials: A
authors.lastname: Tsujimura
authors.forename: Norio
authors.initials: N
authors.lastname: Nonomura
mesh_terms: D000818:Animals; D051546:Cyclooxygenase 2 / Q000096:biosynthesis / Q000235:genetics*; D018856:Cystitis, Interstitial / Q000150:complications / Q000201:enzymology / Q000235:genetics*; D003681:Dehydration / Q000201:enzymology / Q000209:etiology* / Q000235:genetics; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D008297:Male; D012313:RNA / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D001743:Urinary Bladder / Q000201:enzymology*
chemical_list: D012313:RNA; D051546:Cyclooxygenase 2