Nobel prize for work that led to Viagra discovery

THE DISCOVERY that a simple gas - a pollutant in car exhausts - acts as a key chemical messenger in the body has won this year's Nobel prize for medicine.

Three American scientists share the prize for their independent lines of research which led to the finding that nitric oxide can stimulate blood vessels to dilate around the heart and other vital organs when released inside the body.

The work also led to groundbreaking investigations of cardiovascular disease, cancer and the complex chemistry of the male erection, which led to the discovery of the anti-impotence effects of Viagra.

Three pharmacologists, Robert Furchgott, at the State University of New York, Ferid Murad, at the University of Texas Medical School in Houston, and Louis Ignarro, at the University of California, Los Angeles, share the prize of 7.6 million Swedish crowns (pounds 570,000).

Dr Furchgott, now 82, found that some drugs sometimes dilated blood vessels and on other occasions caused them to contract. In 1980 he proposed an unknown "relaxing factor" that could be responsible.

"I'm surprised, although I knew that my name was among those that were up for the prize this year and I guess I had some good friends voting," Dr Furchgott said yesterday.

Dr Murad, 62, discovered in 1977 that some muscle cells release nitric oxide when they relax and speculated that hormones could act on the gas. But it was Dr Ignarro, 57, who performed what the Nobel prize committee called a "brilliant series of analyses" to conclude that nitric oxide was Dr Furchgott's and Dr Murad's mysterious signalling factor.

Since then, nitric oxide has been shown to play a crucial role in the treatment of disorders due to heart problems, shock, lung disease, cancer and impotence.

It is now known that nitroglycerine, a common treatment for cardiovascular disease, works by releasing nitric oxide which increases blood flow to the heart. The Karolinska Institute in Stockholm, which runs the Nobel prize for medicine, said that Alfred Nobel, who set up the prize after inventing dynamite, was advised by doctors a century ago to take nitroglycerine for his chest pains.

"It has been known since the last century that the explosive nitroglycerine has beneficial effects against chest pain. However, it would take 100 years until it was clarified that nitroglycerin acts by releasing the gas," the Karolinska Institute said.