Lung Health News, Spring / Summer 2004
Children who are raised in households with secondhand smoke are at increased risk for developing respiratory diseases of which a cough is a major and frequent symptom. Samuel Evans, MD, is trying to better understand how receptors and chemicals in the brain and lung control cough, hoping to show how exposure to tobacco smoke can change the brain's chemistry.
Coughing is symptomatic of most lung diseases, including asthma, chronic bronchitis, influenza and tuberculosis. It is a complex defensive reflex that occurs in response to foreign material and irritants, including mucus, stimulating sensory receptors in the airways.
"When you accidentally breathe in a drop of water, I'm sure you've noticed a vigorous cough in response to expel the foreign material," the researcher explains. "That drop of water likely stimulated airway receptors, which then sent information to the brain to coordinate the muscle contractions, diaphragm movement, and throat closure required to cough."
The first area to receive the sensory information from the lungs is located in the brain stem. The information is sorted and then sent to higher centers of the brain. Within this circuitry, there are numerous types of connections and neurotransmitters that help organize the information that ultimately triggers a cough. Dr. Evans is studying a specific neurotransmitter in the brain stem.
He works in the laboratory of Jesse Joad, MD, at the University of California, Davis, which recently had its study showing that tobacco smoke may indeed change the brain's chemistry published in the American Journal of Respiratory and Critical Care Medicine. Dr. Evans will present some preliminary results from his project at the American Thoracic Society's Annual Meeting in May.
Research Could Lead to Better Cough Remedies
Dr. Evans, who is a fellow at UC Davis in Pulmonary and Critical Care Medicine, treats patients nearly every day and knows all too well the effect coughing has on their quality of life.
"Coughing is a very bothersome and common complaint for which millions are spent on suppressive remedies, most of which currently are only marginally, if at all, effective," he says. "In order to better treat cough, and perhaps some of the diseases that cause it, we need to better understand the mechanisms that control the behavior."
Dr. Evans received a grant from the American Lung Association of California to conduct his study. This year the association granted more than $750,000 to researchers like Dr. Evans who are conducting basic research into the underlying mechanisms of lung disease. Basic research is an important investment because discoveries made today can lead to better treatments and possibly even cures.
Californians can invest in lung disease research through the Asthma and Lung Disease Research Fund on their 2003 California state income tax returns. The fund is located under Contributions and the money supports the American Lung Association of California's peer-reviewed research program. For more information about the Asthma and Lung Disease Research Fund and a list of currently funded research projects, visit www.californialung.org.
