Value of tachykinin receptor antagonists in the prevention of bronchial hyperresponsiveness, cough and bronchial inflammation.

It is now clearly established that tachykinins of the NANC excitatory syste m play an important role in the airways. They induce bronchoconstriction by activation of NK2 receptors and they induce increased vascular permeabilit y by activation of NK1 receptors. Tachykinins participate in stimulation of secretions and recruitment and activation of inflammatory cells via NK1 an d NK2 effects. All these effects are related to the pathophysiological char acteristics of asthma. Finally, many studies have demonstrated the importan t role of tachykinins in bronchial hyperresponsiveness. Tachykinins are als o involved in the cough mechanism. They exert a significant effect on the s ensitivity of the cough reflex by activating the response related to stimul ation of receptors to irritation. In view of the involvement of NK1 and NK2 receptors in the biological properties of tachykinins on the airways, the use of antagonists with a high affinity for NK1 and NK2 receptors could hav e useful applications. The first results of the therapeutic use of tachykin in receptor antagonists suggest the possible development, of a ne rv therap eutic category in the treatment of asthma, cough and, more generally respir atory tract diseases.