Abstract
Nitroxyl (HNO) donors have potential benefit in the treatment of heart failure and other cardiovascular diseases. 1-Nitrosocyclohexyl acetate (NCA), a new HNO donor, in contrast to the classic HNO donors Angeli’s salt and isopropylamine NONOate, predominantly releases HNO and has a longer half-life. This study investigated the vasodilatative properties of NCA in isolated aortic rings and human platelets and its mechanism of action. NCA was applied on aortic rings isolated from wild-type mice and apolipoprotein E–deficient mice and in endothelial-denuded aortae. The mechanism of action of HNO was examined by applying NCA in the absence and presence of the HNO scavenger glutathione (GSH) and inhibitors of soluble guanylyl cyclase (sGC), adenylyl cyclase (AC), calcitonin gene-related peptide receptor (CGRP), and K+ channels. NCA induced a concentration-dependent relaxation (EC50, 4.4 µM). This response did not differ between all groups, indicating an endothelium-independent relaxation effect. The concentration-response was markedly decreased in the presence of excess GSH; the nitric oxide scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide had no effect. Inhibitors of sGC, CGRP, and voltage-dependent K+ channels each significantly impaired the vasodilator response to NCA. In contrast, inhibitors of AC, ATP-sensitive K+ channels, or high-conductance Ca2+-activated K+ channels did not change the effects of NCA. NCA significantly reduced contractile response and platelet aggregation mediated by the thromboxane A2 mimetic 9,11-dideoxy-11α,9α-epoxymethanoprostaglandin F2α in a cGMP-dependent manner. In summary, NCA shows vasoprotective effects and may have a promising profile as a therapeutic agent in vascular dysfunction, warranting further evaluation.
Footnotes
This work was supported by the Marie Curie Intra European Fellowship within the 7th European Community Framework Programme [PIEF-GA-2008-221666]; the sixth Framework Program of the European Union [Marie Curie EXT-014051]; and the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases [Grant HL62198]. This research was also supported in part by the Intramural Research Program of the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases.
- Received September 17, 2012.
- Accepted November 19, 2012.
- U.S. government work not protected by U.S. copyright.
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