According to a study led by Kentaro Mizuta of Tohoku University’s Graduate School of Dentistry, the sleep hormone melatonin aggravates asthma. The findings were reported in the journal “American Journal of Physiology Lung Cellular and Molecular Physiology.”
Bronchoconstriction is a condition in which the smooth muscles of the bronchus — the tube that transports air to and from your lungs — constrict. Many people use a bronchodilator, a drug that expands the bronchus, to help with this. Melatonin, which is commonly used for insomnia, activated the melatonin MT2 receptor, which favored bronchoconstriction and decreased the relaxing action of a bronchodilator.
The researchers discovered the expression of the melatonin MT2 receptor in human airway smooth muscle to help them figure out what was going on. They discovered that activating the melatonin MT2 receptor with larger dosages of melatonin or the melatonin receptor agonist ramelteon increased bronchoconstriction significantly. Melatonin also reduced the relaxing effects of b-adrenoceptor agonist, a commonly used bronchodilator.
“Although melatonin serum concentration did not significantly promote airway constriction, higher dosages of melatonin, which is therapeutically used to treat insomnia, jet lag, or cancer, aggravated asthma symptoms and reduced the therapeutic impact of bronchodilators,” Mizuta explained.
“Pharmacological medication that blocks the melatonin MT2 receptor could decrease the deleterious effects of melatonin on airways,” said Haruka Sasaki, the paper’s first author.