Airway Receptors and Asthma

Airway caliber is determined by a balance between many constrictor and dilator agents, which bring about their effects on the various target cells of the airway by activating specific cell surface receptors. Asthma and bronchial hyperresponsiveness may be viewed as an imbalance between excitatory and inhibitory receptor-mediated effects on the various target cells in the airway. Airway receptors can be grouped into those mediating the effects of the autonomic nervous system on the airways or those mediating the effects of the various mediators which may be generated in asthma. There is no convincing evidence that a fundamental defect in receptor function is involved in the pathogenesis of asthma, although minor abnormalities have been described. Recently there has been a considerable increase in our understanding of receptor function and control, which should throw light on the pathogenesis of airway obstruction and may lead to advances in asthma therapy. This may also lead to the development of novel drugs for treating asthma in the future.