Role of endothelin in the respiratory system

The bronchomotor tone is the result of a complex interaction between neurotransmitter release and local mediators. The efferent neurohumoral pathways to the muscular, vascular and glandular element include parasympathetic nerves, sympathetic nerves, and non-adrenergic non-cholinergic (NANC) neurotransmission. It is currently recognised that the characteristic features of asthma are airway hyperresponsiveness and inflammatory changes to the airways. An important mediator of these mechanisms is endothelin-1 (ET-1), able to induce bronchoconstriction, airway hyperresponsiveness to histamine and inflammatory cell recruitment. Furthermore, several studies in the literature showed increased levels of ET-1 in bronchoalveolar lavage of asthmatic patients. Therefore, in the light of the involvement of ET-1 in asthmatic disease, it could be suggested that ET-1 receptor antagonists and endothelin converting enzyme (ECE) inhibitors may be useful for investigating mechanisms of bronchopulmonary alterations of asthmatic diseases, and possibly reduce airway hyperresponsiveness in asthmatic patients.