On Oct. 12, 1998, Louis J. Ignarro of the University of California School of Medicine was awarded the 1998 Nobel Prize in Physiology of Medicine with Robert F. Furchgott and Ferid Murad for their discoveries concerning nitric oxide as a signalling molecule in the cardiovascular system.

Nitric oxide (NO) is a gas that transmits signals in the organism. Signal transmission by a gas that is produced by one cell, penetrates through membranes and regulates the function of another cell represents an entirely new principle for signalling in biological systems.