[Role of adenosine in the pathogenesis of bronchial asthma]

Adenosine has been found to contract human bronchial smooth muscle in vitro and to induce bronchoconstriction in asthmatic patients when administered by inhalation. The importance of adenosine for bronchial tone and bronchial reactivity is still unclear. Adenosine seems unlikely to cause bronchoconstriction by a non-specific irritant effect. Some evidence suggests that the action of adenosine relates to a specific pharmacologic activity. Bronchoconstriction induced by adenosine is antagonized by theophylline and is potentiated by dipyridamole. Therapeutic concentrations of theophylline exhibit specificity for adenosine's bronchoconstrictor activity supporting the concept that the bronchospastic effect of adenosine is mediated through stimulation of cell surface receptors. Stimulation of afferent receptors producing vagally mediated reflex seems unlikely. A further explanation of adenosine bronchoconstriction is a release of mediators through potentiation of ongoing mediator release from bronchial luminal mast-cells.