[Nitric oxide (NO), vascular protection factor. Biology, physiological role and biochemistry of NO].
VASOMOTRICITY: The vascular endothelium plays a key role in vasomotricity by producing a number of factors which modulate smooth muscle relaxation and contraction. Nitric oxide (NO) has been found to be one of the most important relaxation factors. NO SYNTHESIS: Nitric oxide is synthesized from L-arginine by NO-synthetase whose activity is regulated by intracellular calcium concentration and modulated by pharmacological compounds such as acetylcholine, 5-hydroxytryptamine, bradykinin and ADP as well as the sheer forces produced by blood flow.
NO stimulates soluble guanylate cyclase in smooth muscles. Its action is mediated by increased intracellular cGMP which provokes smooth muscle relaxation. ACTIONS OF NO: The physiological role of NO produced by the vascular endothelium is quite complex and incompletely elucidated. NO helps maintain adequate blood supply to tissues by reacting rapidly to changes in pharmacological and mechanical stimuli. It opposes the direct vasoconstrictor effect of certain factors in the blood stream and its action on platelets and endogenous fibrinolysis helps prevent thrombus formation.
Tiritilli
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Laboratoire de Physiologie et Pharmacologie cardiovasculaire, Centre Hospitalier, Saint-Germain-en-Laye.
D000818:Animals; D001120:Arginine / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004730:Endothelium, Vascular / Q000502:physiology*; D006162:Guanylate Cyclase / Q000378:metabolism; D006801:Humans; D009130:Muscle, Smooth / Q000201:enzymology; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D014661:Vasoconstriction; D014664:Vasodilation
D009569:Nitric Oxide; D001120:Arginine; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D006162:Guanylate Cyclase; D006152:Cyclic GMP; D002118:Calcium
Le monoxyde d'azote (NO), facteur de protection vasculaire. Biologie, rôles physiologiques et biochimie du NO.