Nitric oxide (NO) is a colorless gas and stable free radical that turns blue when it is liquefied or solidified. It was discovered and studied in 1772 by J. Priestley, who called it “nitrous air”. A toxic gas and air pollutant, NO has many industrial uses, especially in the production of nitric acid.
In the 1980s it was discovered that NO is the active metabolite released from nitroglycerine and amyl nitrite, vasodilators that are used for treating heart conditions such as angina. R. F. Furchgott, L. J. Ignarro, and F. Murad won the 1998 Nobel Prize in Physiology or Medicine for their work on NO’s role as a physiological signaling molecule. NO is released by the noni plant (Morinda citrifolia), which has been used as a “cure-all” by Pacific islanders for thousands of years.
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