title: Activation of P2Y6 Receptors Facilitates Nonneuronal Adenosine Triphosphate and Acetylcholine Release from Urothelium with the Lamina Propria of Men with Bladder Outlet Obstruction.
abstract: OBJECTIVE
  Deregulation of purinergic bladder signaling may contribute to persistent detrusor overactivity in patients with bladder outlet obstruction. Activation of uridine diphosphate sensitive P2Y6 receptors increases voiding frequency in rats indirectly by releasing adenosine triphosphate from the urothelium. To our knowledge this mechanism has never been tested in the human bladder.
  
  
  METHODS
  We examined the role of the uridine diphosphate sensitive P2Y6 receptor on tetrodotoxin insensitive nonneuronal adenosine triphosphate and [(3)H]acetylcholine release from the human urothelium with the lamina propria of control organ donors and patients with benign prostatic hyperplasia.
  
  
  RESULTS
  The adenosine triphosphate-to-[(3)H]acetylcholine ratio was fivefold higher in mucosal urothelium/lamina propria strips from benign prostatic hyperplasia patients than control men. The selective P2Y6 receptor agonist PSB0474 (100 nM) augmented by a similar amount adenosine triphosphate and [(3)H]acetylcholine release from mucosal urothelium/lamina propria strips from both groups of individuals. The facilitatory effect of PSB0474 was prevented by MRS2578 (50 nM) and by carbenoxolone (10 μM), which block P2Y6 receptor and pannexin-1 hemichannels, respectively. Blockade of P2X3 (and/or P2X2/3) receptors with A317491 (100 nM) also attenuated release facilitation by PSB0474 in control men but not in patients with benign prostatic hyperplasia. Immunolocalization studies showed that P2Y6, P2X2 and P2X3 receptors were present in choline acetyltransferase positive urothelial cells. In contrast to P2Y6 staining, choline acetyltransferase, P2X2 and P2X3 immunoreactivity decreased in the urothelium of benign prostatic hyperplasia patients.
  
  
  CONCLUSIONS
  Activation of P2Y6 receptor amplifies mucosal adenosine triphosphate release underlying bladder overactivity in patients with benign prostatic hyperplasia. Therefore, we propose selective P2Y6 receptor blockade as a novel therapeutic strategy to control persistent storage symptoms in obstructed patients.
authors.affiliation: Laboratório de Farmacologia e Neurobiologia, Porto, Portugal; Center for Drug Discovery and Innovative Medicines, Porto, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Silva
authors.affiliation: Laboratório de Farmacologia e Neurobiologia, Porto, Portugal; Center for Drug Discovery and Innovative Medicines, Porto, Portugal.
authors.forename: Fátima
authors.initials: F
authors.lastname: Ferreirinha
authors.affiliation: Laboratório de Farmacologia e Neurobiologia, Porto, Portugal; Center for Drug Discovery and Innovative Medicines, Porto, Portugal.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Magalhães-Cardoso
authors.affiliation: Laboratório de Farmacologia e Neurobiologia, Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto and Serviço de Urologia, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Silva-Ramos
authors.affiliation: Laboratório de Farmacologia e Neurobiologia, Porto, Portugal; Center for Drug Discovery and Innovative Medicines, Porto, Portugal. Electronic address: farmacol@icbas.up.pt.
authors.forename: Paulo
authors.initials: P
authors.lastname: Correia-de-Sá
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000368:Aged; D006801:Humans; D008297:Male; D009092:Mucous Membrane / Q000378:metabolism; D011470:Prostatic Hyperplasia / Q000150:complications; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D001743:Urinary Bladder / Q000378:metabolism*; D001748:Urinary Bladder Neck Obstruction / Q000209:etiology / Q000378:metabolism*; D019459:Urothelium / Q000378:metabolism*
chemical_list: D018048:Receptors, Purinergic P2; C099845:purinoceptor P2Y6; D000255:Adenosine Triphosphate; D000109:Acetylcholine
keywords: acetylcholine; adenosine triphosphate; purinoceptor P2Y6; urinary bladder neck obstruction; urothelium