title: Novel vasocontractile role of the P2Y₁₄ receptor: characterization of its signalling in porcine isolated pancreatic arteries.
abstract: OBJECTIVE
  The P2Y₁₄ receptor is the newest member of the P2Y receptor family; it is G(i/o) protein-coupled and is activated by UDP and selectively by UDP-glucose and MRS2690 (2-thiouridine-5'-diphosphoglucose) (7-10-fold more potent than UDP-glucose). This study investigated whether P2Y₁₄ receptors were functionally expressed in porcine isolated pancreatic arteries.
  
  
  METHODS
  Pancreatic arteries were prepared for isometric tension recording and UDP-glucose, UDP and MRS2690 were applied cumulatively after preconstriction with U46619, a TxA₂ mimetic. Levels of phosphorylated myosin light chain 2 (MLC2) were assessed with Western blotting. cAMP concentrations were assessed using a competitive enzyme immunoassay kit.
  
  
  RESULTS
  Concentration-dependent contractions with a rank order of potency of MRS2690 (10-fold) > UDP-glucose ≥ UDP were recorded. These contractions were reduced by PPTN {4-[4-(piperidin-4-yl)phenyl]-7-[4-(trifluoromethyl)phenyl]-2-naphthoic acid}, a selective antagonist of P2Y₁₄ receptors, which did not affect responses to UTP. Contraction to UDP-glucose was not affected by MRS2578, a P2Y₆ receptor selective antagonist. Raising cAMP levels and forskolin, in the presence of U46619, enhanced contractions to UDP-glucose. In addition, UDP-glucose and MRS2690 inhibited forskolin-stimulated cAMP levels. Removal of the endothelium and inhibition of endothelium-derived contractile agents (TxA₂, PGF(2α) and endothelin-1) inhibited contractions to UDP glucose. Y-27632, nifedipine and thapsigargin also reduced contractions to the agonists. UDP-glucose and MRS2690 increased MLC2 phosphorylation, which was blocked by PPTN.
  
  
  CONCLUSIONS
  P2Y₁₄ receptors play a novel vasocontractile role in porcine pancreatic arteries, mediating contraction via cAMP-dependent mechanisms, elevation of intracellular Ca²⁺ levels, activation of RhoA/ROCK signalling and MLC2, along with release of TxA₂, PGF(2α) and endothelin-1.
authors.affiliation: Life Sciences, University of Nottingham, Nottingham, UK.
authors.forename: M
authors.initials: M
authors.lastname: Alsaqati
authors.forename: M L
authors.initials: ML
authors.lastname: Latif
authors.forename: S L F
authors.initials: SL
authors.lastname: Chan
authors.forename: V
authors.initials: V
authors.lastname: Ralevic
mesh_terms: D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000294:innervation* / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D000242:Cyclic AMP / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000294:innervation* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D010179:Pancreas / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism; D020033:Protein Isoforms / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D058912:Purinergic P2Y Receptor Agonists / Q000737:chemistry / Q000494:pharmacology; D058470:Receptors, Purinergic P2Y / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D015290:Second Messenger Systems / Q000187:drug effects; D034421:Sus scrofa; D014532:Uridine Diphosphate Glucose / Q000819:agonists / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014666:Vasomotor System / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002121:Calcium Channel Blockers; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D058912:Purinergic P2Y Receptor Agonists; D058470:Receptors, Purinergic P2Y; D011994:Recombinant Proteins; D014662:Vasoconstrictor Agents; C547289:diphosphoric acid 1-glucopyranosyl ester 2-((2-thio)uridin-5'-yl) ester; D000242:Cyclic AMP; D014532:Uridine Diphosphate Glucose
keywords: MRS2690; P2Y14 receptor; UDP; UDP-glucose; endothelium; vasoconstriction