Coughing has largely remained a mystery to science. Now, a team in Britain has found that the problem actually lies with receptors on nerve endings in the lungs which react to irritants.

In fact, in their research, involving guinea pigs and human volunteers, the scientists showed that irritants in the air — including cigarette smoke and air pollution — switch on receptor proteins in lung nerve endings called TRPA1. This in turn causes the cough reflex, the ‘Daily Mail’ reported.

When the receptors were blocked in guinea pigs, using drugs, their coughing response to stimulants including a key compound in cigarette smoke was reduced. Nerves taken from mice and humans were also used to back up the research.