Three US scientists who tracked down the chemical that protects the heart, stimulates the brain and led the way to the anti-impotence drug Viagra yesterday shared the $1 million (£653,000) Nobel Prize for Medicine.
Dr Robert Furchgott, now 82, of the State University of New York, and Dr Louis Ignarro (57) of the University of California, Los Angeles, worked separately and together to prove, in 1986, that nitric oxide relaxed muscle cells in the cardiovascular system - a discovery which was a key to understanding why heart drugs worked, or failed.
The third winner, Dr Ferid Murad, now at the University of Texas at Houston, separately discovered in 1977 that nitroglycerin - both an explosive and a heart treatment - released nitric oxide. Nitric oxide is a pollutant from car exhausts, but it has proved to be one of the most important agents in the way the body regulates itself. Its use is being explored in AIDS dementia patients, sickle cell anaemia cases, osteoporosis and malaria. It can also trigger erection of the penis by dilating blood vessels. Viagra is designed to increase nitric oxide's effect.
The prize-winning work, while important for science and medicine, was "a small piece of information" that researchers used in creating Viagra, said Ms Mariann Caprino, spokeswoman for Pfizer Inc which makes Viagra.
The award-winning research has sparked studies on new drugs, including those used for heart problems, atherosclerosis and shock.
"This is a new general principle . . . which will help us to develop lots of new medicines, for example ones that directly relax or retain tension in muscles, as in the new impotence drug, Viagra," said Dr Hans Joernvall, professor of medical chemistry at the Karolinska Institute in Stockholm, where the Nobel assembly meets.
The human immune system uses nitric oxide to kill bacteria, fungi and parasites - and to defend against tumours. But in high concentrations the gas is toxic and occasionally the white blood cells produce so much that the patient goes into sepsis and shock.
The gas has also been used to reduce dangerously high blood pressure in the lungs of infants. It is important in the human sense of smell - and may play a role in establishing memory.
In a paradox of history, Alfred Nobel, the Nobel awards founder, was the inventor of dynamite, which contains nitroglycerin. When he fell ill with heart disease his doctor prescribed nitroglycerin but the inventor refused to take it, arguing that as it caused headaches, it could hardly relieve chest pain.