Researchers have identified the specific neurons that trigger sneezing and coughing in mice.
This discovery marks a significant advancement in our understanding of these fundamental reflexes, with potential implications for managing respiratory symptoms in humans.
Sneezing and coughing are reflexes that protect our respiratory system by expelling irritants, allergens, and pathogens. However, these reflexes also play a role in the spread of infectious diseases, as demonstrated by the COVID-19 pandemic.
Despite their importance, the precise neuronal mechanisms underlying sneezing and coughing have remained elusive—until now.
The new study reveals that sneezing and coughing are driven by distinct neuronal populations. The research team found that the nasal mucosa, which is the tissue lining the nasal cavity, is innervated by several distinct groups of sensory neurons. The researchers found these neurons (MrgprC11+MrgprA3-) to be uniquely responsible for initiating sneezes in response to a variety of nasal irritants, allergens, and viruses. When the neurons were silenced in influenza-infected mice, the animals stopped sneezing altogether.
The study also revealed that the neurons responsible for triggering sneezing do not have a role in inducing coughing. Instead, a separate population of neurons (SST+) is responsible for mediating cough reflexes. This discovery challenges the long-held belief that sneezing and coughing share common sensory receptors and signaling pathways.
The identification of these distinct neuronal pathways opens new avenues for therapeutic interventions aimed at controlling sneezing and coughing, symptoms that can exacerbate the spread of respiratory viral infections. Current treatments for these symptoms are often limited in their effectiveness and can have undesirable side effects, particularly in patients with severe or chronic conditions.
“By targeting the specific neurons responsible for sneezing and coughing, new drugs could be developed to more precisely manage these reflexes without affecting other functions of the respiratory system,” says corresponding author Qin Liu, a professor of anesthesiology at Washington University School of Medicine in St. Louis.
“Such treatments could be especially valuable during outbreaks of respiratory infections, where controlling the spread of the virus is critical.”
The new study represents a significant advancement in our understanding of the sensory and neuronal mechanisms that drive sneezing and coughing. By distinguishing between the neuronal pathways involved in these reflexes, the research not only deepens our knowledge of basic respiratory biology but also provides a foundation for developing targeted therapies that could improve patient outcomes during respiratory infections and allergies.
The research appears in Cell.
