[Inflammatory mediators (leukotrienes, thromboxane A2, tachykinins and others)].

Bronchial asthma is characterized by airway nallowing and hypersensitivity, for the occurrence of which (chemical) mediators are almost entirely responsible. Recent clinical as well as experimental reports have strongly suggested that arachidonate metabolites, especially cysteinyl leukotrienes (CysLTs), are involved in the attack of not only allergic asthma but also exercise- or aspirin-induced asthma. Because the receptor of CysLT1 but not CysLT2 largely contributes to the various pulmonary pharmacological actions of CysLTs, CysLT1 antagonists with high potency have rapidly developed recently. Other chemical mediators, tachykinins, endothelins and so on can be also candidates for the cause of the disease.