Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/123579
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Type: Journal article
Title: Increased superoxide production and altered nitric oxide-mediated relaxation in the aorta of young but not old male relaxin-deficient mice
Author: Ng, H.
Jelinic, M.
Parry, L.
Leo, C.
Citation: American Journal of Physiology - Heart and Circulatory Physiology, 2015; 309(2):H285-H296
Publisher: American Physiological Society
Issue Date: 2015
ISSN: 0363-6135
1522-1539
Statement of
Responsibility: 
Hooi H. Ng, Maria Jelinic, Laura J. Parry and Chen-Huei Leo
Abstract: The vascular effects of exogenous relaxin (Rln) treatment are well established and include decreased myogenic reactivity and enhanced relaxation responses to vasodilators in small resistance arteries. These vascular responses are reduced in older animals, suggesting that Rln is less effective in mediating arterial function with aging. The present study investigated the role of endogenous Rln in the aorta and the possibility that vascular dysfunction occurs more rapidly with aging in Rln-deficient (Rln(-/-)) mice. We compared vascular function and underlying vasodilatory pathways in the aorta of male wild-type (Rln(+/+)) and Rln(-/-) mice at 4 and 16 mo of age using wire myography. Superoxide production, but not nitrotyrosine or NADPH oxidase expression, was significantly increased in the aorta of young Rln(-/-) mice, whereas endothelial nitric oxide (NO) synthase and basal NO availability were both significantly decreased compared with Rln(+/+) mice. In the presence of the cyclooxygenase inhibitor indomethacin, sensitivity to ACh was significantly decreased in young Rln(-/-) mice, demonstrating altered NO-mediated relaxation that was normalized in the presence of a membrane-permeable SOD or ROS scavenger. These vascular phenotypes were not exacerbated in old Rln(-/-) mice and, in most cases, did not differ significantly from old Rln(+/+) mice. Despite the vascular phenotypes in Rln(-/-) mice, endothelium-dependent and -independent vasodilation were not adversely affected. Our data show a role for endogenous Rln in reducing superoxide production and maintaining NO availability in the aorta but also demonstrate that Rln deficiency does not compromise vascular function in this artery or exacerbate endothelial dysfunction associated with aging.
Keywords: aorta; endothelium; nitric oxide; relaxin; superoxide
Rights: © 2015 the American Physiological Society
RMID: 1000004909
DOI: 10.1152/ajpheart.00786.2014
Grant ID: http://purl.org/au-research/grants/arc/LP110200543
Appears in Collections:Environment Institute publications

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