title: Expression and alpha1-adrenoceptor regulation of caldesmon in human prostate smooth muscle.
abstract: OBJECTIVE
  To investigate expression and α1-adrenergic regulation of caldesmon in the human prostate. Caldesmon is an important mediator and regulator of contraction in different smooth muscle types. However, this has not been investigated in the prostate to date. The activity of caldesmon may be tightly regulated by serine-789 phosphorylation.
  
  
  METHODS
  Prostate tissue was obtained from patients undergoing radical prostatectomy. Caldesmon expression was studied by Western blot analysis and immunohistochemistry. The adrenergic regulation of caldesmon phosphorylation was investigated by Western blot analyses with a site- and phosphospecific antibody.
  
  
  RESULTS
  Caldesmon expression was detectable by Western blot analysis in all investigated samples of human prostates (n = 8 patients). Immunoreactivity after staining with a caldesmon antibody was strong in smooth muscle cells, but not observed in glandular or epithelial cells (n = 5 patients). In double fluorescence staining, caldesmon co-localized with α1A-adrenoceptors and α-smooth muscle actin (n = 6 patients). Stimulation of prostate tissue with noradrenaline (30 μM, n = 6 patients) or the α1-adrenergic agonist phenylephrine (10 μM, n = 6 patients) resulted in progressive phosphorylation of caldesmon at serine-789. Noradrenaline-induced caldesmon phosphorylation was 1.5 ± 0.2-fold after 5 minutes (P<.04 vs basal phosphorylation), and 1.6 ± 0.2-fold after 10 minutes (P<.04). Phenylephrine-induced caldesmon phosphorylation was 1.7 ± 0.2-fold after 10 minutes (P<.02 vs basal phosphorylation), and 2.4 ± 0.6-fold after 20 minutes (P<.05).
  
  
  CONCLUSIONS
  Caldesmon is an effector of α1-adrenoceptors in the human prostate. Caldesmon activation may be of importance for α1-adrenergic prostate contraction, and during therapy with α1-blockers.
authors.affiliation: Department of Urology, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Walther
authors.forename: Frank
authors.initials: F
authors.lastname: Strittmatter
authors.forename: Alexander
authors.initials: A
authors.lastname: Roosen
authors.forename: Frauke
authors.initials: F
authors.lastname: Heinzer
authors.forename: Beata
authors.initials: B
authors.lastname: Rutz
authors.forename: Christian G
authors.initials: CG
authors.lastname: Stief
authors.forename: Christian
authors.initials: C
authors.lastname: Gratzke
authors.forename: Martin
authors.initials: M
authors.lastname: Hennenberg
mesh_terms: D058646:Adrenergic alpha-1 Receptor Agonists / Q000494:pharmacology; D015153:Blotting, Western; D002148:Calmodulin-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009130:Muscle, Smooth / Q000502:physiology*; D010656:Phenylephrine / Q000494:pharmacology; D010766:Phosphorylation; D011467:Prostate / Q000502:physiology*; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D058646:Adrenergic alpha-1 Receptor Agonists; D002148:Calmodulin-Binding Proteins; D018340:Receptors, Adrenergic, alpha-1; D010656:Phenylephrine