303 Virgin Olive Oil Benefits birth. Most neural tube defects can be prevented by taking folic acid (folates), a type of B vitamin, in the early stages of pregnancy. NIRS SENSORS (See TECHNOLOGY) NITRATE Nitrate is a chemical compound composed of nitrogen and oxygen. Chemically, it is a salt formed by the reaction between an acid (in the case of nitrates, nitric acid -HNO₃-) and a base (such as sodium hydroxide -also known as caustic soda-). water (water -H2O--) H H O salt (sodium nitrate -Na NO3 -) -O O-Na+ O N+ + base (sodium hydroxide -NaOH-) acid (nitric acid - HNO3 -) + HO OO N+ Na H O neutralisation hydrolysis (H: hydrogen; N: nitrogen; Na: sodium; O: oxygen) NITRIC OXIDE Nitric oxide, also known as nitrogen monoxide or nitrogen oxide (NO), was initially recognised as an atmospheric pollutant, as it is produced during petrol combustion, contributing to “smog” and acid rain, and thus to the degradation of the ozone layer. Although toxic in air, it is surprising that a molecule with such harmful characteristics can also play a wide range of beneficial roles in the mammalian body, particularly due to its effect on blood vessel dilation (vasodilation). In the body, nitric oxide is produced by several types of cells (such as endothelial, nervous, and epithelial, etc. cells) from the amino acid L-arginine, in a reaction catalysed by the enzyme Nitric Oxide Synthase (NOS), in the presence of oxygen. NO is constitutively expressed in certain cells (such as endothelial and nerve cells), while in others it is normally absent or present only in minimal amounts. However, in those other cells, its synthesis can be induced under certain conditions, such as inflammation or infection. We now know that nitric oxide is involved in various physiological and pathological processes. It acts as an intracellular and intercellular messenger and contributes to blood vessel dilation (vasodilation) by relaxing the vascular smooth muscle of the endothelium. Physical exercise stimulates the production of nitric oxide, thereby improving the delivery of oxygen and energy substrates to the muscles. It also inhibits platelet aggregation (platelets are blood cells that initiate thrombotic processes -see “Platelet function” and “Thrombosis”-). In the central nervous system, nitric oxide serves several functions. It acts as a neurotransmitter (a chemical messenger between neurons) and regulates cerebral blood flow by counteracting vasoconstriction, ensuring a constant supply of blood to the brain. It is also involved in the inflammatory response and in immune system function. For example, macrophages (a type of white blood cell that destroys microorganisms and clears dead
RkJQdWJsaXNoZXIy Njg1MjYx