Role of nitric oxide in airway inflammation and hyperresponsiveness in bronchial asthma

Nitric oxide (NO) is produced within the airways and has a variety of actions on the airway function. Nitric oxide is a potent bronchodilator, and NO released from airway epithelial cells and inhibitory nonadrenergic non-cholinergic nerve terminals may attenuate airway hyperresponsiveness. However, a large amount of NO produced by inducible NO synthase may facilitate airway inflammation, which then leads to airway hyperresponsiveness. Although the role of NO remains controversial, the measurement of exhaled NO may well be of value in the clinical management of asthma.