title: Phasic contractions in urinary bladder from juvenile versus adult pigs.
abstract: OBJECTIVE
  Alterations in properties of the bladder with maturation are relevant physiologically and pathophysiologically. The aim of this study was to investigate alterations in bladder properties with maturation in juvenile vs. adult pig, focussing on differences between layers of the bladder wall (mucosa vs. detrusor) and the presence and functional contribution of interstitial cells (ICs).
  
  
  METHODS
  Basal and cholinergic-induced phasic contractions (PCs) in mucosal and denuded-detrusor strips from juvenile and adult pigs were assessed. Expression of c-kit, a marker of ICs, was investigated in the mucosa and the detrusor layers of the pig bladder. The functional role of ICs in mediating PCs was examined using imatinib.
  
  
  RESULTS
  Mucosal strips from juvenile and adult pig bladders demonstrated basal PCs whilst denuded-detrusor strips did not. PCs of mucosal strips from juvenile pigs were significantly greater than those from adult bladders. Immunoreactivity for c-kit was detected in mucosa and detrusor layers of pig bladder. Histological studies demonstrated a distinct layer of smooth muscle between the urothelium and bladder detrusor, termed the muscularis mucosa. Imatinib was only effective in inhibiting PCs in mucosal strips from juvenile pigs. Imatinib inhibited the carbachol-induced PCs of both juvenile and adult denuded-detrusor strips, although strips from juvenile bladders demonstrated a trend towards being more sensitive to this inhibition.
  
  
  CONCLUSIONS
  We confirm the presence of c-kit positive ICs in pig urinary bladder. The enhanced PCs of mucosal strips from juvenile animals could be due to altered properties of ICs or the muscularis mucosa in the bladders of these animals.
authors.affiliation: Department of Applied Sciences, University of the West of England, Bristol, United Kingdom. Bahareh.vahabi@uwe.ac.uk
authors.forename: Bahareh
authors.initials: B
authors.lastname: Vahabi
authors.forename: Donna J
authors.initials: DJ
authors.lastname: Sellers
authors.forename: Dominika A
authors.initials: DA
authors.lastname: Bijos
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Drake
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D000068877:Imatinib Mesylate; D066298:In Vitro Techniques; D009092:Mucous Membrane / Q000187:drug effects / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D010879:Piperazines / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D019009:Proto-Oncogene Proteins c-kit / Q000037:antagonists & inhibitors; D011743:Pyrimidines / Q000494:pharmacology; D013552:Swine; D001743:Urinary Bladder / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*
chemical_list: D001549:Benzamides; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D002217:Carbachol; D019009:Proto-Oncogene Proteins c-kit