Functional NOS 1 in the rat mesenteric arterial bed.
Previously we have demonstrated functional nitric oxide synthase (NOS) 1 in large arteries. Because resistance arteries largely determine blood pressure, this study examined whether functional NOS 1 also exists in resistance arteries. Phenylephrine (PE) contraction was measured in the absence and presence of the NOS 1 inhibitor N(5)-(1-imino-3-butenyl)-L-ornithine (VNIO) in isolated mesenteric resistance arteries (endothelium intact and denuded) from Sprague-Dawley rats. For NOS 1 activity and expression, the mesenteric arterial bed was separated into cytosolic and particulate fractions. NOS activity was assayed by measuring the conversion of [(3)H]arginine to [(3)H]citrulline inhibited by a nonselective NOS inhibitor or VNIO. VNIO increased PE sensitivity in endothelium-intact and -denuded arteries. In cytosolic and particulate fractions of the arterial bed, approximately 40% of NOS activity was inhibited by VNIO. Immunoprecipitation and Western blot analysis revealed two NOS 1 immunoreactive bands. One band corresponded to the rat brain isoform, whereas the second was of a slightly lower molecular mass. The cytosolic fraction contained both isoforms; however, the particulate fraction had only the lower molecular mass form. These studies demonstrate the existence of functional NOS 1 in resistance arteries.
Vascular Biology Center, Medical College of Georgia, 1459 Laney-Walker Boulevard, Augusta, GA 30912, USA. jsullivan@mail.mcg.edu
Jennifer C
JC
Sullivan
Ararat D
AD
Giulumian
David M
DM
Pollock
Leslie C
LC
Fuchs
Jennifer S
JS
Pollock
D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000201:enzymology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D009952:Ornithine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011233:Precipitin Tests; D051381:Rats; D017207:Rats, Sprague-Dawley; D013347:Subcellular Fractions / Q000201:enzymology; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D004791:Enzyme Inhibitors; C111862:N(5)-(1-imino-3-butenyl)ornithine; D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D009952:Ornithine; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat