born May 31, 1941, Brooklyn, N.Y., U.S.
U.S. pharmacologist.
He earned a Ph.D. from the University of Minnesota. Along with Robert F. Furchgott and Ferid Murad , Ignarro was awarded a 1998 Nobel Prize for the discovery that nitric oxide acts as a signaling molecule in the cardiovascular system. Ignarro concluded that the factor that Furchgott had named endothelium-derived relaxing factor was nitric oxide. This work uncovered an entirely new mechanism by which blood vessels in the body relax and widen. It was the first discovery that a gas could act as a signaling molecule in a living organism. The principle behind the drug Viagra , used to treat impotence, was based upon this research.