nitric oxide

noun

, Chemistry.

1. a colorless, slightly water-soluble gas, NO, formed by the action of dilute nitric acid on copper, and by the direct combination of atmospheric oxygen and nitrogen at the high temperatures of an electric arc: an intermediate in the manufacture of nitric acid.

nitric oxide

noun

1. a colourless slightly soluble gas forming red fumes of nitrogen dioxide in air. Formula: NO Systematic namenitrogen monoxide

nitric oxide

1. A colorless, poisonous gas produced as an intermediate compound during the manufacture of nitric acid from ammonia or from atmospheric nitrogen. It is also produced through cellular metabolism. In the body, nitric oxide is involved in oxygen transport to the tissues, the transmission of nerve impulses, and other physiological activities. Chemical formula: NO.

Word History and Origins

Origin of nitric oxide¹

First recorded in 1800–10

A Closer Look

While nitric oxide (NO) was once regarded solely as a poisonous air pollutant, responsible for the formation of photochemical smog and acid rain leading to the destruction of the ozone layer, today it is also appreciated as a molecule essential to human health. Nitric oxide is the first gas discovered to act as a signaling molecule, a transmitter of important signals to cells in various systems of the human body. Even though NO continues to be detrimental to the environment, it was heralded as Science Magazine 's Molecule of the Year in 1992, and the Nobel Prize for physiology or medicine was awarded in 1998 to the three scientists who discovered that NO works as a signaling molecule in the cardiovascular system. It is now known that the cells of a blood vessel's inner walls use NO to signal the vessel to relax and dilate, increasing blood flow. Nitroglycerin, whose effectiveness in treating heart problems was once a mystery, is now known to work by releasing NO. NO has a variety of other important biological functions, including destroying bacteria within the immune system and acting as a neurotransmitter.

Example Sentences

Even substances that don’t look like well-known signals might act as messengers, as scientists learned when it turned out that gases such as nitric oxide can affect organs.

From Science Magazine

The port and the company are currently negotiating Norwegian’s contribution to the project — a welcome gesture given previous years of emitting carbon and sulfur dioxide, nitric oxide and other harmful particulate matter on Seattle’s waterfront.

From Seattle Times

The multiple health benefits of leafy greens are partly because spinach, lettuce and beetroots are brimming with nitrate, which can be reduced to nitric oxide by nitrate-reducing bacteria inside the mouth.

From Salon

The team explains that the high local temperature activates the other active agent, BNN-6, to release nitric oxide molecules that open the channel in the endoplasmic reticulum.

From Science Daily

In humans, cytoglobin is involved in processes involving nitric oxide, a compound that helps regulate healthy blood flow to organs.

From Science Daily