Scientists at Washington University in St. Louis and the University of Iowa have found that human lungs contain odor receptors called pulmonary neuroendocrine cells (PNECs).

Unlike the receptors in the human nose, which are located in the membranes of nerve cells, PNECs are located in the membranes of neuroendocrine cells. And, instead of sending nerve impulses to the brain that allow it to perceive smells – much like odor receptors found in the nose – PNECs trigger neuroendocrine cells to release hormones that make the body’s airways constrict.

The researchers, led by Yehuda Ben-Sharar, PhD, assistant professor of biology and medicine at Washington University, believe PNECs might be responsible for the chemical hypersensitivity prevalent in respiratory diseases, such COPD and asthma. Patients with these diseases are told to avoid traffic fumes, pungent odors, perfumes, and similar irritants, which can trigger airway constriction and breathing difficulties.

“We forget that our body plan is a tube within a tube, so our lungs and our gut are open to the external environment,” said Ben-Shahar. “Although they’re inside us, they’re actually part of our external layer. So they constantly suffer environmental insults, and it makes sense that we evolved mechanisms to protect ourselves.”

Ben-Shahar and his team of researchers also suggest that the odor receptors on the PNEC cells might be a therapeutic target. “By blocking them, it might be possible to prevent some attacks, allowing people to cut down on the use of steroids or bronchodilators,” he added.