Methylxanthines induce bronchospasmolytic effects in asthmatic patients due to their nonspecific inhibition of phosphodiesterases and a subsequent increase in intracellular levels of the second messenger cAMP. Methylxanthines also increase ciliary beat frequency and stimulate mucociliary transport. Previous studies have demonstrated overstimulation and damage to tracheal goblet cells as well as a substantial decrease in the [...]