Ignarro, together with fellow American pharmacologists Robert Furchgott and Ferid Murad, received the 1998 Nobel Prize in Physiology or Medicine for discoveries related to the role of nitric oxide as a signaling molecule in the cardiovascular system.

Not to be confused with nitrous oxide (a gas used in anesthesia), nitric oxide is a colorless, odorless gas that, thanks to initial work by these three Nobel laureates and a flurry of subsequent research by others, now has widespread potential including the treatment of heart disease, shock, cancer, impotence, and pulmonary hypertension--a potentially fatal condition in premature infants. In 1994, the respected journal Science declared nitric oxide as its "molecule of the year."

Born in Brooklyn, New York, Ignarro studied pharmacy at Columbia University and then obtained a Ph.D. in Pharmacology from the University of Minnesota. He served as professor of pharmacology at Tulane University in New Orleans from 1979 to 1985, when...