title: Alpha1 -adrenergic receptors mediate bladder overactivity induced by cold stress in rats with bladder outlet obstruction.
abstract: OBJECTIVE
  To determine if alpha1 -adrenergic receptors (AR) mediate bladder overactivity induced by cold stress in rats with bladder outlet obstruction (BOO).
  
  
  METHODS
  The urethras of 10-week-old female Sprague-Dawley rats were ligated to create BOO. After 4 weeks, cystometric investigations were performed at room temperature (RT, 27 ± 2°C) for 20 min. The rats were then given 0.3 mg/kg naftopidil (n = 6) or vehicle (n = 5) intravenously. Five minutes later, they were transferred to low temperature (LT, 4 ± 2°C), and the cystometric patterns were again recorded for 40 min. In BOO rats and in sham-operated rats (n = 8) the expression levels of alpha1A - and alpha1D -AR mRNAs and the presence of alpha1A - and alpha1D -AR immunoreactivity on calcitonin gene-related peptide (CGRP)-positive nerve cells were investigated.
  
  
  RESULTS
  During LT exposure, the vehicle-treated BOO rats exhibited cold stress-induced bladder overactivity. In the naftopidil-treated rats, the increase of basal pressure and decreases of both voiding interval and bladder capacity induced by LT were significantly reduced compared to the vehicle-treated animals. In the bladders of BOO rats exposed to LT, the expression of alpha1D -AR mRNA was significantly higher than in sham-operated rats, and the immunoreactivity for alpha1D -ARs on the CGRP-positive nerve cells tended to be more pronounced.
  
  
  CONCLUSIONS
  Alpha1 -ARs mediate part of the bladder overactivity induced by cold stress in rats with BOO. Cold stress increases the expression of alpha1D -AR mRNA and the immunoreactivity for alpha1D -ARs on the CGRP-positive nerve cells in BOO rats. Naftopidil partially inhibits the cold stress overactivity, suggesting that it is mediated, at least partially, through alpha1D/1A -ARs.
authors.affiliation: Department of Urology, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yamagishi
authors.forename: Osamu
authors.initials: O
authors.lastname: Ishizuka
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Imamura
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Ogawa
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kurizaki
authors.forename: Osamu
authors.initials: O
authors.lastname: Nishizawa
authors.forename: Karl-Erik
authors.initials: KE
authors.lastname: Andersson
mesh_terms: D000818:Animals; D003080:Cold Temperature; D005260:Female; D051381:Rats; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D001743:Urinary Bladder / Q000503:physiopathology*; D001748:Urinary Bladder Neck Obstruction / Q000503:physiopathology*; D053201:Urinary Bladder, Overactive / Q000209:etiology / Q000503:physiopathology*
chemical_list: D018340:Receptors, Adrenergic, alpha-1
keywords: alpha1-adrenergic receptors; bladder outlet obstruction; cold stress; overactive bladder; rats