The researchers found that nitric oxide, a gas present in car exhausts, cigarette smoke and industrial emissions, is produced in the main nerve of the penis and causes the organ to expand when stimulated.
Doctors had previously thought that the nerves controlling erections worked in the same way as those controlling other involuntary actions, Charles Lowenstein, a medical researcher at Johns Hopkins University School of Medicine in Maryland, said.
But research published in the current issue of the journal Science proves that there is an altogether different mechanism at work, he said. 'This work shows that this alternative network of nerves controlled by nitric oxide is reponsible for erections. It is completely bizarre for a molecule to be floating around the body as a gas.'
Erections result when two cavities within the penis become flooded with blood as a result of nerve stimulation. The research shows that nitric oxide is the key intermediary in the process.
Overproduction of nitric oxide could be responsible for priapism, when men suffer from painful, prolonged erections that are not associated with sexual arousal or desire, Dr Lowenstein said. He and his colleagues at Johns Hopkins University - Arthur Burnett, David Bredt, Thomas Chang and Solomon Snyder - believe that it could be possible to cure priapism 'within one or two years' by blocking nitric oxide production in the penis.
There are already drugs that can block the enzyme responsible for making nitric oxide by the body and these could be taken by priapism sufferers with little or no side-effects, he said.
The research finding also suggests that it is possible to treat some impotent men by administering nitric oxide, he said. 'This study does not propose a direct cure for impotence but suggests a way to go about treatment.'Reuse content