title: Interactions between cholinergic and prostaglandin signaling elements in the urothelium: role for muscarinic type 2 receptors.
abstract: OBJECTIVE
  To characterize the interactions between the cholinergic and prostaglandin signaling systems within the urothelium-lamina propria of the guinea pig and elucidate the role of muscarinic receptors in these interactions.
  
  
  METHODS
  The urothelium-lamina propria was isolated from guinea pig bladders, cut into strips (5×10 mm), and maintained in vitro. The tissue was either stretched or left unstretched but exposed to 2'(3')-O-(4-benzoylbenzoyl)adenosine-5'-triphosphate tri(triethylammonium) salt, arecaidine, and prostaglandin E2 (PGE2). Acetylcholine and PGE2 release was measured using a GeneBLAzer M3 CHO-K1-bla cell reporter assay and an enzyme immunoassay, respectively. The role of the muscarinic type 2 and 3 (M2 and M3, respectively) receptors and nitric oxide in mediating PGE2 release was determined in the presence of the muscarinic antagonists 11-[(2-[(diethylamino)methyl]-1-piperidinyl)acetyl]-5,11-dihydro-6H-pyrido[2,3b][1,4] benzodiazepin-6-one and darafenicin and a nitric oxide donor (NONOate).
  
  
  RESULTS
  Acetylcholine release was detected in response to stretch and in the unstretched preparations exposed to PGE2 or the adenosine triphosphate analog 2'(3')-O-(4-benzoylbenzoyl)adenosine-5'-triphosphate tri(triethylammonium) salt. The cholinergic agonist arecaidine induced a concentration-dependent production of PGE2 (half-maximal concentration 75 nM). The arecaidine stimulation of PGE2 production was inhibited in a dose-dependent manner by the antagonist AFDX-116 (M2>M3; half-maximal inhibition 110 nM) but not darifenacin (M3>>M2). Finally, in the presence of the nitric oxide donor, NONOate, arecaidine-stimulated PGE2 production was inhibited.
  
  
  CONCLUSIONS
  These observations demonstrate that complex signal interactions occur within the urothelium involving acetylcholine, adenosine triphosphate, nitric oxide, and PGE2. In addition, the data have demonstrated a role for muscarinic M2 receptors and nitric oxide in the cholinergic regulation of PGE2 production in the bladder wall.
authors: Urophysiology Research Group, Newcastle University Medical and Dental School, Newcastle upon Tyne, Tyne and Wear, United Kingdom.
authors: C J
authors: CJ
authors: Nile
authors: J I
authors: JI
authors: Gillespie
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D015232:Dinoprostone / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006168:Guinea Pigs; D023421:Models, Animal; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D011897:Random Allocation; D043585:Receptor, Muscarinic M2 / Q000187:drug effects / Q000378:metabolism*; D012680:Sensitivity and Specificity; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D046509:Tissue Culture Techniques; D019459:Urothelium / Q000187:drug effects / Q000378:metabolism*
chemical_list: D018727:Muscarinic Antagonists; D043585:Receptor, Muscarinic M2; D009569:Nitric Oxide; D015232:Dinoprostone; D000109:Acetylcholine