title: Effect of long-term prazosin and yohimbine administration on c-Fos expression in spinal neurons: inhibitory effect of alpha-1 and alpha-2 adrenoceptors on afferents from the lower urinary tract.
abstract: BACKGROUND
  To investigate the effects of long-term administration of the α(1)-adrenoceptor antagonist prazosin and the α(2)-adrenoceptor antagonist yohimbine on afferent inputs from the lower urinary tract by evaluating c-Fos expression in the spinal cord.
  
  
  METHODS
  Prazosin or yohimbine was administered for 4 weeks in rats using an osmotic pump. Effects of these agents on urodynamic parameters were determined by continuous cystometry in conscious rats. After cystometry, c-Fos expression in the dorsal horn of the L6 spinal cord was measured by immunohistochemistry.
  
  
  RESULTS
  The administration of prazosin (0.12 mg/kg/day) or yohimbine (0.10 mg/kg/day) significantly increased micturition interval and bladder capacity, but did not affect micturition pressure and residual urine volume. The numbers of c-Fos-positive neurons in the dorsal horn were significantly lower in rats that received prazosin than in controls. Yohimbine reduced the number of c-Fos-positive neurons in part of the dorsal horn.
  
  
  CONCLUSIONS
  Long-term administration of prazosin and yohimbine at clinically recommended doses can exert inhibitory effects on afferent pathways from the lower urinary tract during the storage phase. These reductions of the afferent input result in the increased bladder capacity and increased micturition interval.
authors.affiliation: Department of Urology, Fukushima Medical University School of Medicine, Fukushima, Japan. pessoco@fmu.ac.jp
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Haga
authors.forename: Ken
authors.initials: K
authors.lastname: Aikawa
authors.forename: Keiichi
authors.initials: K
authors.lastname: Shishido
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Yanagida
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Kushida
authors.forename: Norio
authors.initials: N
authors.lastname: Takahashi
authors.forename: Junji
authors.initials: J
authors.lastname: Yazaki
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamaguchi
mesh_terms: D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology; D058669:Adrenergic alpha-2 Receptor Antagonists / Q000494:pharmacology; D000818:Animals; D005260:Female; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009475:Neurons, Afferent / Q000378:metabolism; D011224:Prazosin / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism; D018341:Receptors, Adrenergic, alpha-2 / Q000378:metabolism; D013116:Spinal Cord / Q000187:drug effects; D013131:Spine / Q000473:pathology; D014551:Urinary Tract / Q000378:metabolism*; D014554:Urination; D015016:Yohimbine / Q000494:pharmacology*
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D016760:Proto-Oncogene Proteins c-fos; D018340:Receptors, Adrenergic, alpha-1; D018341:Receptors, Adrenergic, alpha-2; D015016:Yohimbine; D011224:Prazosin