Abstract 16263: Role for β3-Receptor Activation in ATP-Mediated Endothelial Nitric Oxide Release
Background: Endothelial-dependent nitric oxide (NO) release regulates vasodilation and slows atherogenesis. Cellular ATP has been shown to stimulate NO release through an autocrine pathway involving purinergic P2Y-receptor activation; however, other mechanisms may be involved, including β3-receptor activation. In this study, we evaluated the role of β3-receptors in ATP-mediated NO release using β3-specific agonists and antagonists.
Methods: The comparative effects of β3- and P2Y-receptor activation on NO release from human umbilical vein endothelial cells (HUVECs) were tested using amperometric nanosensors. ATP-dependent NO release was evaluated using suramin (10 µM), a P2Y receptor blocker, and SR59230A (1.0 µM), a β3-receptor antagonist. We also measured the comparative effects of ATP and L-755,507, a β3-receptor agonist, on HUVEC NO release.
Results: ATP treatment increased NO release in a dose-dependent fashion. At the lowest concentration tested (100 nM), ATP increased NO release to 79 ± 6 nM (p<0.01) as compared to vehicle treatment alone (18 ± 2 nM); at the highest dose tested (10 µM), ATP increased NO release to 290 ± 15 nM (p<0.01). Suramin significantly inhibited ATP-induced NO release by approximately 50% at all ATP concentrations tested. Similar effects were observed with the β3-receptor antagonist, SR59230A, which reduced ATP-induced NO release by 32% (186 ± 11 nM to 126 ± 23 nM, p<0.001) and 45% (290 ± 15 nM to 160 ± 21 nM, p<0.001) at 1.0 and 10.0 µM ATP levels, respectively. The β3-receptor agonist, L-755,507 caused a dose-dependent increase in extracellular ATP release that correlated with changes in NO production.
Conclusion: ATP promoted a dose-dependent increase in NO release that was significantly inhibited by both P2Y- and β3-receptor antagonists. The effects of ATP on NO release were reproduced by a β3-receptor agonist, which also stimulated endogenous ATP release. These data indicate a novel role for β3-receptors in ATP-mediated endothelial NO production.
- © 2011 by American Heart Association, Inc.