Novel vasocontractile role of the P2Y₁₄ receptor: characterization of its signalling in porcine isolated pancreatic arteries

Abstract

BACKGROUND AND PURPOSEThe P2Y14 receptor is the newest member of the P2Y receptor family; it is Gi/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. EXPERIMENTAL APPROACHPancreatic 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. KEY RESULTSConcentration-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, PGF2α 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 AND IMPLICATIONSP2Y14 receptors play a novel vasocontractile role in porcine pancreatic arteries, mediating contraction via cAMP-dependent mechanisms, elevation of intracellular Ca 2+ levels, activation of RhoA/ROCK signalling and MLC2, along with release of TxA2, PGF2α and endothelin-1.

Ovariectomy uncovers purinergic receptor activation of endothelin-dependent natriuresis

“…Despite their overlapping spheres of influence, information on potential interplay between renal P2 and ET receptors is rare. The interaction between ET-1 and P2 signaling systems has been also demonstrated in extrarenal tissues (1,4,31,35). Our current findings demonstrate that activation of medullary P2 receptors promotes ET-1-dependent natriuresis in OVX rats, similar to male rats (23).…”

Characterization of the contractile P2Y14 receptor in mouse coronary and cerebral arteries

“…2B). EC 50 values are not reported for the effect of UDP‐glucose in porcine arteries [12]. However, the EC 50 values seem to be similar to those observed here in the fresh coronary arteries.…”

“…3); this may be a future avenue of research. In recent work by Alsaqati and colleagues [12], a partially endothelium‐dependent UDP‐glucose contraction was observed. Although the role of the endothelium was not directly investigated in this study, we performed a correlation analysis between the endothelium function and the E max of UDP‐glucose (Figs.…”

The G Protein-coupled Receptor P2Y14 Influences Insulin Release and Smooth Muscle Function in Mice

“…2A) and significant increases in blood pressure and heart rate of P2Y 14 -deficient mice (supplemental Table S1). There is some evidence that P2Y 14 may have vasocontractile function on arteries (36), but P2Y 14 expression in smooth muscle cells in arteries is controversially discussed (37,38). We found some ␤-galactosidase positive arteries only in lung and CNS (circulus arteriosus Willisii) (data not shown).…”