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Vascular distribution of nitric oxide synthase and vasodilation in the Australian lungfish, Neoceratodus forsteri

journal contribution
posted on 2008-12-01, 00:00 authored by Brett Jennings, R Blake, J Joss, John DonaldJohn Donald
The presence of nitric oxide synthase (NOS) and role of nitric oxide (NO) in vascular regulation was investigated in the Australian lungfish, Neoceratodus forsteri. No evidence was found for NOS in the endothelium of large and small blood vessels following processing for NADPH-diaphorase histochemistry. However, both NADPH-diaphorase histochemistry and neural NOS immunohistochemistry demonstrated a sparse network of nitrergic nerves in the dorsal aorta, hepatic artery, and branchial arteries, but there were no nitrergic nerves in small blood vessels in tissues. In contrast, nitrergic nerves were found in non-vascular tissues of the lung, gut and kidney. Dual-wire myography was used to determine if NO signalling occurred in the branchial artery of N. forsteri. Both SNP and SIN-1 had no effect on the pre-constricted branchial artery, but the particulate guanylyl cyclase (GC) activator, C-type natriuretic peptide, always caused vasodilation. Nicotine mediated a dilation that was not inhibited by the soluble GC inhibitor, ODQ, or the NOS inhibitor, L-NNA, but was blocked by the cyclooxygenase inhibitor, indomethacin. These data suggest that NO control of the branchial artery is lacking, but that prostaglandins could be endothelial relaxing factors in the vasculature of lungfish.

History

Journal

Comparative biochemistry and physiology. Part A : molecular & integrative physiology

Volume

151

Issue

4

Pagination

590 - 595

Publisher

Elsevier Science

Location

New York, N.Y.

ISSN

1095-6433

eISSN

1531-4332

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2008, Elsevier