US research, using mice, has examined which neurons in our airways trigger different sneezing and coughing reflexes.

Sneezing and coughing are protective reflexes which help us to avoid various diseases, and the study from Washington University in St Louis (WashU), Missouri, and Georgia Institute of Technology, used small molecules to activate a type of receptor (MrgprC11) found on the surface of neurons in the nasal airways, that triggers sneezing. 

Mice, which had been genetically altered to not have this sneeze-activating MrgprC11 receptor in their nasal neurons, were infected with the flu virus and although they grew sick, they did not sneeze. This was a strong sign that the researchers had found the right receptor in neurons responsible for sneezing.

In the study, published in Cell, a similar approach identified another type of receptor (SST) present on the surface of neurons in the trachea that induced coughing and not sneezing, suggesting that the sneezing and coughing pathways are separate.

Lead researcher Qin Liu, from WashU School of Medicine, who has been studying these protection mechanisms for a while, previously said: “Better understanding what causes us to sneeze — specifically how neurons behave in response to allergens and viruses — may point to treatments capable of slowing the spread of infectious respiratory diseases via sneezes.”