Mechanisms of nitric oxide-mediated neurogenic,vasodilation in mesenteric resistance arteries of toad, Bufo marinus
Data(s) |
01/03/2010
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Resumo |
This study determined the role of nitric oxide (NO) in neurogenic vasodilation in mesenteric resistance arteries of the toad <i>Bufo marinus</i>. NO synthase (NOS) was anatomically demonstrated in perivascular nerves, but not in the endothelium. ACh and nicotine caused TTX-sensitive neurogenic vasodilation of mesenteric arteries. The ACh-induced vasodilation was endothelium-independent and was mediated by the NO/soluble guanylyl cyclase signaling pathway, inasmuch as the vasodilation was blocked by the soluble guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one and the NOS inhibitors N<sup>ω</sup>- nitro-L-arginine methyl ester and N<sup>ω</sup>-nitro-L-arginine. Furthermore, the ACh-induced vasodilation was significantly decreased by the more selective neural NOS inhibitor N<sup>5</sup>-(1-imino-3-butenyl)-L-ornithine. The nicotine-induced vasodilation was endothelium-independent and mediated by NO and calcitonin gene-related peptide (CGRP), inasmuch as pretreatment of mesenteric arteries with a combination of N<sup>ω</sup>-nitro-L-arginine and the CGRP receptor antagonist CGRP-(8–37) blocked the vasodilation. Clotrimazole significantly decreased the ACh-induced response, providing evidence that a component of the NO vasodilation involved Ca<sup>2+-</sup>activated K<sup>+ </sup>or voltage-gated K<sup>+ </sup>channels. These data show that NO control of mesenteric resistance arteries of toad is provided by nitrergic nerves, rather than the endothelium, and implicate NO as a potentially important regulator of gut blood flow and peripheral blood pressure. |
Identificador | |
Idioma(s) |
eng |
Publicador |
American Physiological Society |
Relação |
http://dro.deakin.edu.au/eserv/DU:30032912/donald-mechanismsof-2010.pdf http://dx.doi.org/10.1152/ajpregu.00148.2009. |
Direitos |
2010, American Physiological Society |
Palavras-Chave | #amphibian #autonomic nervous system #nitric oxide synthase #endothelium |
Tipo |
Journal Article |