Your nose is not the only organ in your body that can sense cigarette smoke wafting through the air. Scientists at Washington University in St. Louis and the University of Iowa have showed that your lungs have odor receptors as well.
Unlike the receptors in your nose, which are located in the membranes of nerve cells, the ones in your lungs are in the membranes of neuroendocrine cells. Instead of sending nerve impulses to your brain that allow it to "perceive" the acrid smell of a burning cigarette somewhere in the vicinity, they trigger the flask-shaped neuroendocrine cells to dump hormones that make your airways constrict.
The newly discovered class of cells expressing olfactory receptors in human airways, called pulmonary neuroendocrine cells, or PNECs, were found by a team led by Yehuda Ben-Sharar, PhD, assistant professor of biology and medicine at Washington University in St. Louis, and including colleagues Steven L. Brody and Michael J. Holtzman of the Washington University School of Medicine, and Michel J. Welsh of the Lucille A. Carver College of Medicine at the University of Iowa.
"We forget," said Ben-Shahar, "that our body plan is a tube within a tube, so our lungs and our gut are open to the external environment. Although they're inside us, they're actually part of our external layer. So they constantly suffer environmental insults," he said, "and it makes sense that we evolved mechanisms to protect ourselves."
In other words, the PNECs, described in the March issue of the American Journal of Respiratory Cell and Molecular Biology, are sentinels, guards whose job it is to exclude irritating or toxic chemicals.
The cells might be responsible for the chemical hypersensitivity that characterizes respiratory diseases, such chronic obstructive pulmonary disease (COPD), and asthma. Patients with these diseases are told to avoid traffic fumes, pungent odors, perfumes and similar irritants, which can trig
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Washington University in St. Louis