title: Neuronal and non-neuronal bradykinin receptors are involved in the contraction and/or relaxation to the pig bladder neck smooth muscle.
abstract: OBJECTIVE
  The current study investigates the role played by bradykinin (BK) receptors in the contractility to the pig bladder neck smooth muscle.
  
  
  METHODS
  Bladder neck strips were mounted in myographs for isometric force recordings and BK receptors expression was also determined by immunohistochemistry.
  
  
  RESULTS
  B2 receptor expression was observed in the muscular layer and urothelium whereas B1 expression was consistent detected in urothelium. A strong B2 immunoreactivity was also observed within nerve fibers among smooth muscle bundles. On urothelium-denuded preparations basal tone, BK induced concentration-dependent contractions which were reduced in urothelium-intact samples, by extracellular Ca(2+) removal and by blockade of B2 receptors and voltage-gated Ca(2+) (VOC) and non-VOC channels, and increased by cyclooxygenase (COX) inhibition. On phenylephrine-precontracted denuded strips, under non-adrenergic non-cholinergic (NANC) conditions, electrical field stimulation-elicited frequency-dependent relaxations which were reduced by B2 receptor blockade. In urothelium-intact samples, the B1 receptor agonist kallidin promoted concentration-dependent relaxations which were reduced by blockade of B1 receptors, COX, COX-1 and large-conductance Ca(2+) -activated K(+) (BKCa ) channels and abolished in urothelium-denuded samples and in K(+) -enriched physiological saline solution-precontracted strips.
  
  
  CONCLUSIONS
  These results suggest that BK produces contraction of pig bladder neck via smooth muscle B2 receptors coupled to extracellular Ca(2+) entry via VOC and non-VOC channels with a minor role for intracellular Ca(2+) mobilization. Facilitatory neuronal B2 receptors modulating NANC inhibitory neurotransmission and urothelial B1 receptors producing relaxation via the COX-1 pathway and BKCa channel opening are also demonstrated. Neurourol. Urodynam. 33:558-565, 2014. © 2013 Wiley Periodicals, Inc.
authors.affiliation: Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Ana S F
authors.initials: AS
authors.lastname: Ribeiro
authors.forename: Vítor S
authors.initials: VS
authors.lastname: Fernandes
authors.forename: María Pilar
authors.initials: MP
authors.lastname: Martínez
authors.forename: Ana
authors.initials: A
authors.lastname: Martínez-Sáenz
authors.forename: María Ruth
authors.initials: MR
authors.lastname: Pazos
authors.forename: Luis M
authors.initials: LM
authors.lastname: Orensanz
authors.forename: Paz
authors.initials: P
authors.lastname: Recio
authors.forename: Salvador
authors.initials: S
authors.lastname: Bustamante
authors.forename: Joaquín
authors.initials: J
authors.lastname: Carballido
authors.forename: Albino
authors.initials: A
authors.lastname: García-Sacristán
authors.forename: Dolores
authors.initials: D
authors.lastname: Prieto
authors.forename: Medardo
authors.initials: M
authors.lastname: Hernández
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D065168:Bradykinin Receptor Antagonists / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D051545:Cyclooxygenase 1 / Q000378:metabolism; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D043783:Receptor, Bradykinin B1 / Q000378:metabolism* / Q000502:physiology; D043782:Receptor, Bradykinin B2 / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction; D013552:Swine; D001743:Urinary Bladder / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D019459:Urothelium / Q000187:drug effects / Q000378:metabolism*
chemical_list: D065168:Bradykinin Receptor Antagonists; D015220:Calcium Channels; D051036:Large-Conductance Calcium-Activated Potassium Channels; D043783:Receptor, Bradykinin B1; D043782:Receptor, Bradykinin B2; D051545:Cyclooxygenase 1; D011451:Prostaglandin-Endoperoxide Synthases; D001920:Bradykinin; D002118:Calcium
keywords: bladder neck; bradykinin receptors; neuronal; smooth muscle contractility; urothelial and smooth muscle receptors and inhibitory neurotransmission modulation