Louis Joseph Ignarro (1941- present) was awarded one-third of the 1998 Nobel Prize in Physiology or Medicine for the discovery that nitric oxide acts as a signaling molecule in the cardiovascular system. Ignarro showed that the factor that fellow Nobel Laureate Robert F. Furchgott had named "endothelium-derived relaxing factor" was in fact nitric oxide. Nitric oxide signals the smooth muscle cells in blood vessel walls to relax, thereby dilating the vessels. This was the first discovery that a gas could act as a signaling molecule in a living organism. The findings allowed researchers to examine nitric oxide's ability to improve treatments for heart disease, shock, and cancer.