The study was carried out on guinea pigs and human volunteers. The researchers report that the presence of a receptor called TRPA 1 on nerve endings in the lungs is linked to a sudden fit of coughing. Exposure to irritants in the atmosphere like air pollution and cigarette smoke activate these receptors, which in turn activate the cough reflex.

A positive finding in the study is that when these receptors were blocked in guinea pigs through certain drugs, the cough reflex was not triggered even when the animals were exposed to the same irritants.

Professor Maria Belvisi, of the National Heart and Lung Institute and Imperial College, London and a co-author of the study said blocking these receptors may be a way to cure cough.“For some people chronic coughing can be annoying and uncomfortable, but for others it can be distressing and can have a severe impact on the quality of their life," she added. "We think that we have cracked the mechanism, we can start investigating whether we can stop people from coughing excessively by blocking the receptor protein that triggers it.”

The details of the study appear in the American Journal of Respiratory and Critical Care Medicine.

Cough is an act of spewing out air in a forceful manner from the lungs. It is a defense mechanism, which allows people to clear out lungs when exposed to unwanted substances like cigarette smoke. In such situations, cough is a protective mechanism, but there are some situations when cough is repetitive and is unwanted. it is in such patients that blocking the TRPA 1 receptors may actually have therapeutic value.