Beta-adrenoceptors and the epithelial layer in airways

Life Sci. 1993;52(26):2123-30. doi: 10.1016/0024-3205(93)90727-k.

Abstract

As an inflammatory disorder of the respiratory system, asthma is characterized by bronchial hyper-responsiveness that appears to involve alterations of the bronchial epithelium. The existence of epithelial beta-receptors is of particular importance to respiratory function, and epithelial dysfunction in asthma may impair beta-adrenoceptor function and lead to bronchial hyper-responsiveness. After reviewing the structure and function of the respiratory epithelium and the role of epithelial beta-adrenoceptors, an in vitro model allowing the detailed study of the regulation of airway smooth muscle by epithelial cells is described. Studies with this model have demonstrated that epithelial beta-adrenoceptors participate in modulating the tone of bronchial smooth muscle cells. Activation of these beta-adrenoceptors leads to bronchial myorelaxation, probably mediated by one or more inhibitory substances generated within the epithelium. In addition, beta-adrenoceptor activity may affect smooth muscle tone indirectly by regulating mucociliary clearance and the paracellular exchange of inflammatory mediators. Since some respiratory diseases seem to be associated with beta-adrenoceptor dysfunction, therapy with beta-agonists may be beneficial by acting on beta-adrenoceptors located both on smooth muscle cells and on epithelial cells.

Publication types

  • Review

MeSH terms

  • Animals
  • Asthma / physiopathology*
  • Bronchial Hyperreactivity / physiopathology
  • Epithelium / physiology
  • Humans
  • Receptors, Adrenergic, beta / physiology*
  • Respiratory System / physiopathology*

Substances

  • Receptors, Adrenergic, beta