Open AccessSmall caliber arterial endothelial cells calcium signals elicited by PAR 2 are preserved from endothelial dysfunction
Author(s) -
Hennessey John C.,
Stuyvers Bruno D.,
McGuire John J.
Publication year - 2015
Publication title -
pharmacology research and perspectives
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.975
H-Index - 27
ISSN - 2052-1707
DOI - 10.1002/prp2.112
Subject(s) - vasodilation , acetylcholine , chemistry , muscarinic acetylcholine receptor , endocrinology , transient receptor potential channel , calcium in biology , medicine , receptor , calcium , voltage dependent calcium channel , endothelium , angiotensin ii , ruthenium red , biology , biochemistry
Abstract Endothelial cell ( EC )‐dependent vasodilation by proteinase‐activated receptor 2 ( PAR 2) is preserved in small caliber arteries in disease states where vasodilation by muscarinic receptors is decreased. In this study, we identified and characterized the PAR 2‐mediated intracellular calcium (Ca 2+ )‐release mechanisms in EC from small caliber arteries in healthy and diseased states. Mesenteric arterial EC were isolated from PAR 2 wild‐type ( WT ) and null mice, after saline (controls) or angiotensin II (Ang II ) infusion, for imaging intracellular calcium and characterizing the calcium‐release system by immunofluorescence. EC Ca 2+ signals comprised two forms of Ca 2+ ‐release events that had distinct spatial‐temporal properties and occurred near either the plasmalemma (peripheral) or center of EC . In healthy EC , PAR 2‐dependent increases in the densities and firing rates of both forms of Ca 2+ ‐release were abolished by inositol 1,4,5‐ trisphosphate receptor ( IP 3 R) inhibitor, but partially reduced by transient potential vanilloid channels inhibitor ruthenium red ( RR ). Acetylcholine (ACh)‐induced less overall Ca 2+ ‐release than PAR 2 activation, but enhanced selectively the incidence of central events. PAR 2‐dependent Ca 2+ ‐activity, inhibitors sensitivities, IP 3 R, small‐ and intermediate‐conductance Ca 2+ ‐activated potassium channels expressions were unchanged in EC from Ang II WT . However, the same cells exhibited decreases in ACh‐induced Ca 2+ ‐release, RR sensitivity, and endothelial nitric oxide synthase expression, indicating Ang II ‐induced dysfunction was differentiated by receptor, Ca 2+ ‐release, and downstream targets of EC activation. We conclude that PAR 2 and muscarinic receptors selectively elicit two elementary Ca 2+ signals in single EC . PAR 2‐selective IP 3 R‐dependent peripheral Ca 2+ ‐release mechanisms are identical between healthy and diseased states. Further study of PAR 2‐selective Ca 2+ ‐release for eliciting pathological and/or normal EC functions is warranted.