Thesis
Characterisation of P2 receptors that modulate vascular tone in pulmonary arteries
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2022
- Thesis identifier
- T16170
- Person Identifier (Local)
- 201569478
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Purinergic P2Y receptors are a family of eight G protein-coupled receptors (P2Y1,2,4,6,11,12,13,14) that are activated by nucleotides to elicit both vasoconstriction and vasodilation. The role of individual P2Y subtypes in these actions is unclear due to the poor selectivity of most antagonists available. The aim of this project was to determine the role of P2Y2 receptors in nucleotide-evoked vascular responses using the novel P2Y2 receptor antagonist, AR-C118925XX. First, its pharmacological actions were characterised using intracellular Ca2+ imaging as a bioassay. Uridine 5’-triphosphate (UTP) acted at recombinant P2Y2 receptors stably expressed in 1321N1 cells to evoked concentration-dependent rises in Ca2+. AR-C118925XX had no effect per se on intracellular Ca2+, but reversibly and competitively antagonised the actions of UTP (pA2=8.43, KB=3.7 nM). 1 µM ARC118925XX had no effect at native or recombinant hP2Y1, hP2Y4, rP2Y6 or hP2Y11 receptors. Next, the role of native P2Y2 receptors in the vascular actions of nucleotides was investigated. AR-C118925XX inhibited UTP-evoked Ca2+ mobilisation in human EAhy926 vascular endothelial cells (KB=3.0 nM). UTP, uridine 5’-diphosphate (UDP) and adenosine 5’-triphosphate (ATP) elicited contractions of rat isolated intrapulmonary and tail arteries at resting tone that were both unaffected by ARC118925XX (1 µM). At raised tone, AR-C118925XX (1 µM) partially inhibited endothelium-dependent vasodilation of intrapulmonary arteries evoked by UTP and UDP, but had no effect on responses to ATP and ADP. At raised tone, these agonists caused vasoconstriction rather than vasodilation of tail arteries. These data show that AR-C118925XX is a potent, selective and competitive P2Y2 receptor antagonist. They also demonstrate that P2Y2 receptors do not mediate contraction of intrapulmonary and systemic arteries, and that they are natively expressed in vascular endothelial cells, where they mediate Ca2+ mobilisation and vasodilation. As the only selective P2Y2 antagonist available, AR‐C118925XX will be invaluable in identifying the functions of P2Y2 receptors function and their potential as a novel therapeutic target.
- Advisor / supervisor
- Kennedy, Charles
- Resource Type
- DOI
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