263 MODULATION OF UROTHELIAL ATP RELEASE AND ITS PARACRINE ACTION BY PURINERGIC AND MUSCARINIC NEUROTRANSMITTERS

Abstract

You have accessJournal of UrologyBladder and Urethra: Anatomy, Physiology and Pharmacology I1 Apr 2012263 MODULATION OF UROTHELIAL ATP RELEASE AND ITS PARACRINE ACTION BY PURINERGIC AND MUSCARINIC NEUROTRANSMITTERS Guiping Sui, Chris Fry, Bruce Montgomery, and Changhao Wu Guiping SuiGuiping Sui Guildford, United Kingdom More articles by this author , Chris FryChris Fry Guildford, United Kingdom More articles by this author , Bruce MontgomeryBruce Montgomery Frimley, United Kingdom More articles by this author , and Changhao WuChanghao Wu Guildford, United Kingdom More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.320AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Urothelium has been recognised as an active sensory structure and pivotal to the signal transduction is ATP release from the urothelium. However, the functional pathways for ATP release mediated by the receptors identified in the urothelium are poorly understood and its paracrine action has never been characterised. This study used native urothelium to test the hypothesis that major urothelial receptors exert significant control over ATP release which further elicits a paracrine effect. METHODS Human bladder mucosal samples were obtained by cystoscopy with ethics approval and patient consent. Guinea-pig (2-3 month old) urothelial sheets and muscle strips were isolated by blunt dissection. Urothelial cells were freshly dissociated from the urothelial sheets. All preparations were superfused in a physiological saline. A tension transducer was used to record contractions. ATP was measured by sampling the superfusate adjacent to the urothelium and using a luciferin-luciferase assay. Intracellular Ca2+ was measured in urothelial cells with Fura-2. RESULTS Substantial intrinsic ATP release was observed in human (369±97 pmoles/g tissue, n=9 subjects) and guinea-pig urothelium (563±78 pmoles/g, n=46 bladders). P2Y specific agonist UTP increased ATP release (human: 308±34% of control, n=5, p<0.01; guinea-pig: 268±61%, n=11, p<0.01). P2X agonist α,β-methylene ATP had no effect. These effects were mirrored by UTP-evoked intracellular Ca2+ rise in urothelial cells. Muscarinic activator carbachol also generated ATP release (human: 512±121% of control, n=7, p<0.05; guinea-pig: 195±23%, n=38, p<0.01). This effect was mimicked by M2 preferential agonist oxotremorine and antagonised by methoctramine (M2), but not by 4-DAMP (M3). Carbachol produced little effect on intracellular Ca2+ but generated mucosal contractions that correlated with ATP release. Urothelium-attached but not urothelium-denuded smooth muscle exhibited intrinsic contractile activities that were augmented by sub-threshold concentrations of carbachol which had little effect on the smooth muscle; these activities were attenuated by desensitizing P2X receptors on the smooth muscle. CONCLUSIONS Purinergic and muscarinic neurotransmitters exert significant control over urothelial ATP release, mediated by P2Y and M2 receptors. Released ATP produces a paracrine effect on the underlying structures. Whilst intracellular Ca2+ rise may contribute to ATP release via purinergic receptors, mucosal contraction is more likely to underlie ATP release by muscarinic receptors. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e107 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Guiping Sui Guildford, United Kingdom More articles by this author Chris Fry Guildford, United Kingdom More articles by this author Bruce Montgomery Frimley, United Kingdom More articles by this author Changhao Wu Guildford, United Kingdom More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...