Measurement and pharmacology of mucociliary clearance

Airways mucociliary clearance (MCC), which continuously removes inhaled particles and cellular debris from the lungs is impaired in a number of diseases such as bronchitis, asthma and cystic fibrosis. Regulation of MCC under normal conditions is not well understood and the cause of its impairment is ill defined. Animal models have been used to study the regulatory mechanisms of both mucus secretion and MCC and to ascertain the involvement of neural pathways. Cholinergic stimulation is a most effective means of enhancing MCC in molluscs, frogs and mammals including man. Recent data from mammals suggest that MCC is also regulated by neuropeptides either directly (substance P) or by facilitating the stimulatory effect of cholinergic agents. A better understand of basic regulatory mechanisms of MCC is vital to an understanding of its impairment in respiratory diseases.