The Nobel Prize in Physiology or Medicine 1998
"for their discoveries concerning nitric oxide as a signalling molecule in the cardiovascular system"
Robert F. Furchgott, Louis J. Ignarro, and Ferid Murad received the Nobel Prize in Physiology or Medicine in 1998 for their discovery that nitric oxide (NO) is a signalling molecule responsible for dilation of blood vessels. (See How Viagra Works.)
Furchgott and Ignarro independently established that nitric oxide was the active stimulatory molecule in vasodilation. Murad recognized that the stimulatory effect of nitroglycerine on cGMP levels was due to the fact that nitroglycerine produced nitric oxide inside the cell. Nitroglycerine had long been used to treat high blood pressure. In fact, Alfred Nobel, the discoverer of nitroglycerine and the founder of the Nobel Prizes, was treated with nitroglycerine for this problem.