Ignarro, who was born in Brooklyn, New York, graduated with a BA in pharmacy from Columbia University in 1962 and four years later gained his PhD in pharmacology at the University of Minnesota. From 1979 to 1985 he worked in the department of pharmacology at Tulane University School of Medicine, New Orleans. Since 1985 he has been at the UCLA School of Medicine, Los Angeles, California. In 1998 he shared the Nobel Prize for physiology or medicine with Robert Furchgott and Ferid Murad for their discovery that molecules of the gas nitrogen monoxide (nitric oxide, NO) can transmit signals in the cardiovascular system. The hitherto unknown substance endothelium-derived relaxing factor (EDRF) had been discovered by Furchgott in 1980. Ignarro made a series of brilliant analyses to determine the chemical nature of EDRF and in 1986 concluded, independently of and together with Furchgott, that the mystery substance was indeed nitrogen monoxide.