pertaining to or containing nitrogen in one of its higher valences.
nitric acid a highly caustic, fuming acid that has a characteristic choking odor and can be fatal if swallowed. It is sometimes used as a cauterizing agent in the eradication of warts; large amounts of it on the skin can cause necrosis. It is also used in the form of its potassium and sodium salts. The antidote for nitric acid poisoning is liberal application of an alkali or sodium bicarbonate.
nitric oxide 1.
NO, a naturally occurring gas that in the body is a short-lived dilator released from vascular epithelial cells in response to the binding of vasodilators to endothelial cell receptors; it causes inhibition of muscular contraction, and thus relaxation. Excesses of nitric oxide are toxic to cells of the central nervous system and also cause the drop in blood pressure seen in septic shock. Called also endothelial-
or endothelium-derived relaxing factor
2. a preparation of nitric oxide used together with ventilatory support or other agents in the treatment of respiratory failure due to persistent fetal circulation in term and near-term neonates; administered by inhalation.
ni·tric ox·ide (NO·), (nī'trik oks'īd),
A colorless free-radical gas that reacts rapidly with O2 to form other nitrogen oxides (e.g., NO2, N2O3, N2O4) and ultimately is converted to nitrite (NO2-) and nitrate (NO3-); a gaseous mediator of cell-to-cell communication and potent vasodilator, formed from l-arginine in bone, brain, endothelium, granulocytes, pancreatic beta cells, and peripheral nerves by a constitutive nitric oxide synthase, and in hepatocytes, Kupffer cells, macrophages, and smooth muscle by an inducible nitric oxide synthase (e.g., induced by endotoxin). NO· activates soluble guanylate cyclase, mediates penile erection, and may be the first known retrograde neurotransmitter.
The short-lived NO molecule is a product of various tissues and plays a role in various processes. NO elaborated by endothelium, which is identical to endothelium-derived relaxing factor (EDRF), dilates vessels by relaxing vascular smooth muscle. Nitrites used in coronary and peripheral vascular disease induce or mimic this action. The 1998 Nobel Prize in Medicine or Physiology was awarded to three U.S. pharmacologists, Robert F. Furchgott, Ferid Murad, and Louis J. Ignarro, for their independent discoveries of the role of NO in cardiovascular physiology. In the immune system, macrophages use NO as a cytotoxic agent. Deficiency or inactivation of NO may contribute to the pathogenesis of both hypertension and atherosclerosis. An excess of NO, which is a free radical, is toxic to brain cells, and NO is also responsible for the precipitate, often fatal drop in blood pressure accompanying septic shock. Free NO in the bloodstream is rapidly reduced by the iron of hemoglobin.
nitric oxide (NO)1
a colorless gas and stable free radical commonly found in tissues of humans and other mammals. It is also prepared commercially by passing air through an electric arc. Biologically the effector molecule is commonly synthesized from the amino acid arginine. NO participates in many biological functions, such as neurotransmission, vasodilation, cytotoxicity of macrophages, lipid-lowering therapy, and inhibition of platelet aggregation. NO is involved in smooth muscle action and penile erection. It may improve oxygenation in patients with high-altitude pulmonary edema. NO deprivation may lead to high blood pressure and the formation of atherosclerotic plaque. On contact with air, NO is quickly converted to the very poisonous nitrogen dioxide (NO2).
nitric oxide (NO)2
a respiratory inhalant.
indications It is used in combination with other agents and ventilatory support in the treatment of full-term and near-term (34 weeks) neonates with hypoxic respiratory failure associated with pulmonary hypertension.
contraindications Two factors that prohibit its use are dependence on right-to-left shunting of blood and known hypersensitivity.
adverse effects Life-threatening effects are pulmonary hemorrhage, intracranial hemorrhage, sepsis, stridor, methemoglobinemia, seizures, cerebral infarction, and posttreatment infection. Other adverse effects include atelectasis, hematuria, hyperglycemia, cellulitis, withdrawal syndrome, and hypotension.
nitric oxide A multifaceted bioregulatory agent and environmental pollutant capable of causing genotoxicity.
A gas byproduct of high-temperature combustion (e.g., internal combustion engines) which, on exposure to light, results in nitrous oxide (N2O) formation, an irritating air pollutant and major greenhouse gas.
A neurotransmitter released when glutamate binds to the NMDA receptor, which is critical in regulating vascular tone.
nitric oxide A multifaceted bioregulatory agent and environmental pollutant, capable of causing genotoxicity Environment A gas byproduct of high temperature combustion–eg, internal combustion engines which, on exposure to light, results in NO2 formation, an irritating air pollutant, and major greenhouse gas Physiology Endothelium-derived relaxing factor A neurotransmitter released when glutamate binds to the NMDA receptor, which is critical in regulating vascular tone. See Nitric oxide synthase.
ni·tric ox·ide (nī'trik ok'sīd)
A colorless, free-radical gas; it reacts rapidly with O2 to form other nitrogen oxides (e.g., NO2·, N2O3, and N2O4) and ultimately is converted to nitrite (NO2-) and nitrate (NO3-). Physiologically, it is a naturally occurring vasodilator formed in endothelial cells, macrophages, neutrophils, and platelets, and a mediator of cell-to-cell communication formed in bone, brain, endothelium, granulocytes, pancreatic β-cells, and peripheral nerves.
nitric oxide Nitrogen monoxide (NO), one of the eight oxides of nitrogen consisting of a single nitrogen atom and a single oxygen atom. In 1987 nitric oxide was found to be an important physiological mediator, a relaxant of smooth muscle in the walls of blood vessels that was derived from the inner lining (endothelium) of blood vessels. Later it was shown that nitric oxide was far more than simply an endothelium-derived relaxing factor (EDRF). Three different enzymes synthesize nitric oxide, from endothelium, nerves and macrophages and the NO produced has actions all over the body. Nitric oxide is involved in controlling blood pressure; in the phagocytic action of MACROPHAGES; in inhibiting PLATELET aggregation and hence blood clotting; in limiting the development of ATHEROSCLEROSIS; in controlling the heart action; in relaxing the smooth muscle in the air tubes of the lungs and the walls of the intestine; in a range of brain functions; and in promoting penile erection (see SILDENAFIL).
nitric oxide powerful vasoconstrictor released by vascular endothelium
pertaining to or containing nitrogen in one of its higher valences.
a highly caustic, fuming acid that has a characteristic choking odor. It was used at one time in the immediate treatment of rabid animal bites to prevent rabies becoming established, and as a cauterizing agent in the eradication of various kinds of warts. It is also used in the form of its potassium and sodium salts. It can be fatal if swallowed, and large amounts of nitric acid applied to the skin can cause necrosis. The antidote for nitric acid poisoning is an alkali or sodium bicarbonate applied liberally.
is produced during the ensiling process and animals in confined spaces and exposed to silo gas may develop severe respiratory disease due to irritation of the alveolar epithelium. Called also silo-filler's disease. See also atypical interstitial pneumonia