title: The expression of β3-adrenoceptors and their function in the human prostate.
abstract: BACKGROUND
  Little is known about β3-adrenoceptor (AR) expression and function in human prostate. We examined the expression and distribution of β-AR subtypes in normal prostate and benign prostatic hyperplasia (BPH) tissues, and investigated which selective β-AR subtype agonist was most involved in the relaxation of isolated human prostate strips.
  
  
  METHODS
  Messenger RNA (mRNA) expression for β1-, β2-, and β3 -ARs was investigated using reverse transcriptase-polymerase chain reactions (RT-PCR). Quantitative analysis of mRNA expression of β-AR subtypes between normal prostate and BPH tissues was performed using quantitative RT-PCR (qPCR). Distributions were examined by immunohistochemistry (IHC). Strips of human normal prostate or BPH were suspended in organ baths and exposed to isoproterenol, dobutamine, procaterol, and TRK-380 to investigate their relaxant effects on KCl-induced contractions, and their inhibitory effects on electrical field stimulation (EFS)-induced contractions.
  
  
  RESULTS
  We confirmed the presence of mRNA for β1-, β2-, and β3-ARs both in normal prostate and in BPH tissues. For β3-AR, mRNA expression in BPH tissues was significantly higher than in normal prostate tissues, but there was no significant difference in β1- and β2-AR expression between normal and BPH tissues. IHC revealed differences in staining intensity between smooth muscle cells and glandular cells, with different proportions for different β-AR subtypes. Staining of β3-AR was particularly intense in smooth muscle cells as opposed to glandular cells. Isoproterenol and TRK-380 significantly decreased the tone of KCl-induced contractions of the normal prostate strips. The rank order of relaxant effects was isoproterenol > TRK-380 > procaterol > dobutamine. All selective β-AR agonists significantly decreased the amplitude of EFS-induced contractions of the normal prostate strips. The rank order of inhibitory effects was isoproterenol > dobutamine >TRK-380 > procaterol. In BPH strips, all selective β-AR agonists showed no significant relaxant or inhibitory effects on KCl- or EFS-induced contractions.
  
  
  CONCLUSIONS
  β3 -AR is abundant in human prostate smooth muscle, whose relaxation is mediated by β1- and β3-AR stimulation. β3-AR agonists may have clinical use in the treatment of male non-BPH patients or neurogenic bladder patients with voiding dysfunction.
authors.affiliation: Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Otsuka
authors.affiliation: Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Rikiya
authors.initials: R
authors.lastname: Matsumoto
authors.affiliation: Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Furuse
authors.affiliation: Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Ozono
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000368:Aged; D000369:Aged, 80 and over; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009924:Organ Culture Techniques; D011467:Prostate / Q000187:drug effects / Q000502:physiology*; D022702:Receptors, Adrenergic, beta-3 / Q000096:biosynthesis*
chemical_list: D000318:Adrenergic beta-Agonists; D022702:Receptors, Adrenergic, beta-3
keywords: adrenoceptors; benign prostatic hyperplasia; immunohistochemistry; polymerase chain reaction; prostate