title: Uropathogenic Escherichia coli alters muscle contractions in rat urinary bladder via a nitric oxide synthase-related signaling pathway.
abstract: BACKGROUND
  Uropathogenic Escherichia coli (UPEC) is a common cause of urinary-tract infection. The mechanisms by which bacteria cause the symptoms of cystitis remain unclear.
  
  
  METHODS
  The contractions of isolated rat detrusor strips evoked by electrical field stimulations (EFS) or by exogenous agonists and immunoblotting for the detection of protein expression in the bladder were measured in the short (1 h) and long (24 h) term after the intravesical instillation of J96 (O4:K6) strain or UPEC isolated from patients with acute E. coli pyelonephritis or E. coli lipopolysaccharide (LPS).
  
  
  RESULTS
  One hour after the instillation of UPEC, the level of endothelial nitric oxide synthase (eNOS) and the contractile response, but not protein kinase C (PKC) and extracellular signal-regulated kinase (ERK)-1/2 activation, were higher. Twenty-four hours after UPEC treatment, detrusor contractions were decreased, and inducible (i) NOS protein expression and ERK1/2 phosphorylation, but not PKC activation, were observed. Both aminoguanidine and PD98059 treatment markedly reversed the decrease of EFS- and acetylcholine-evoked detrusor contractions induced by UPEC. The instillation of LPS triggered PKC activation but not ERK1/2 phosphorylation.
  
  
  CONCLUSIONS
  Short-term intravesical instillation of UPEC enhances detrusor contractions through an eNOS-related pathway, but iNOS-regulated ERK1/2 signaling may be involved in long-term UPEC treatment-induced responses. There are different mechanisms involved in the responses induced by UPEC and LPS.
authors.affiliation: Department of Emergency Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, 10043, Taiwan.
authors.forename: Te I
authors.initials: TI
authors.lastname: Weng
authors.forename: Wen Jone
authors.initials: WJ
authors.lastname: Chen
authors.forename: Hsiao Yi
authors.initials: HY
authors.lastname: Wu
authors.forename: Shing-Hwa
authors.initials: SH
authors.lastname: Liu
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004926:Escherichia coli; D004927:Escherichia coli Infections / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000503:physiopathology; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D001743:Urinary Bladder / Q000378:metabolism* / Q000503:physiopathology; D014552:Urinary Tract Infections / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D019001:Nitric Oxide Synthase; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3