Vasodilator mechanisms in the dorsal aorta of the giant shovelnose ray, Rhinobatus typus (Rajiformes; Rhinobatidae) Donald, John A., Broughton, Brad R. S. and Bennett, Michael B. 2004, Vasodilator mechanisms in the dorsal aorta of the giant shovelnose ray, Rhinobatus typus (Rajiformes; Rhinobatidae), Comparative biochemistry and physiology. Part A : molecular and integrative physiology, vol. 137, no. 1, pp. 21-31, doi: 10.1016/S1095-6433(03)00260-5. Attached Files Name Description MIMEType Size Downloads Title Vasodilator mechanisms in the dorsal aorta of the giant shovelnose ray, Rhinobatus typus (Rajiformes; Rhinobatidae) Author(s) Donald, John A. orcid.org/0000-0001-5930-2642 Broughton, Brad R. S. Bennett, Michael B. Journal name Comparative biochemistry and physiology. Part A : molecular and integrative physiology Volume number 137 Issue number 1 Start page 21 End page 31 Total pages 11 Publisher Elsevier Place of publication New York, N.Y. Publication date 2004-01 ISSN 1095-6433 1531-4332 Summary This study investigated the nature of previous termvasodilator mechanismsnext term in the dorsal aorta of the giant shovelnose ray, Rhinobatus typus. Anatomical techniques found no evidence for an endothelial nitric oxide synthase, but neural nitric oxide synthase was found to be present in the perivascular nerve fibres of the dorsal aorta and other arteries and veins using both NADPH-diaphorase staining and immunohistochemistry with a specific neural NOS antibody. Arteries and veins both contained large nNOS-positive nerve trunks from which smaller nNOS-positive bundles branched and formed a plexus in the vessel wall. Single, varicose nNOS-positive nerve fibres were present in both arteries and veins. Within the large bundles of both arteries and veins, groups of nNOS-positive cell bodies forming microganglia were observed. Double-labelling immunohistochemistry using an antibody to tyrosine hydroxylase showed that nearly all the NOS nerves were not sympathetic. Acetylcholine always caused constriction of isolated rings of the dorsal aorta and the nitric oxide donor, sodium nitroprusside, did not mediate any dilation. Addition of nicotine (3×10−4 M) to preconstricted rings caused a vasodilation that was not affected by the nitric oxide synthase inhibitor, Image -NNA (10−4 M), nor the soluble guanylyl cyclase inhibitor, ODQ (10−5 M). This nicotine-mediated vasodilation was, therefore, not due to the synthesis and release of NO. Disruption of the endothelium significantly reduced or eliminated the nicotine-mediated vasodilation. In addition, indomethacin (10−5 M), an inhibitor of cyclooxygenases, significantly increased the time period to maximal dilation and reduced, but did not completely inhibit the nicotine-mediated vasodilation. These data support the hypothesis that a prostaglandin is released from the vascular endothelium of a batoid ray, as has been described previously in other groups of fishes. The function of the nitrergic innervation of the blood vessels is not known because nitric oxide does not appear to regulate vascular tone. Language eng DOI 10.1016/S1095-6433(03)00260-5 Field of Research 060603 Animal Physiology - Systems HERDC Research category C1.1 Refereed article in a scholarly journal Copyright notice ©2003, Elsevier Persistent URL http://hdl.handle.net/10536/DRO/DU:30025773 Document type: Journal Article Collections: Faculty of Science, Engineering and Built Environment School of Life and Environmental Sciences Related Links Link Description Connect to published version (restricted access) Go to link with your DU access privileges     Unless expressly stated otherwise, the copyright for items in DRO is owned by the author, with all rights reserved. Versions Version Filter Type Thu, 25 Mar 2010, 15:00:26 EST Tue, 30 Mar 2010, 10:41:26 EST Thu, 01 Apr 2010, 14:50:30 EST Sun, 04 Apr 2010, 15:53:58 EST Mon, 16 Jun 2014, 15:03:04 EST Filtered Full Citation counts:   Cited 23 times in TR Web of Science Cited 27 times in Scopus Search Google Scholar Access Statistics: 855 Abstract Views, 0 File Downloads  -  Detailed Statistics Created: Thu, 25 Mar 2010, 15:00:26 EST

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