We Investigated the hypothesis that prior airway muscarinic receptor stimulation (with
aerosolized methacholine) would modify the bronchoconstrictor response to histamine,
which is, in part, vagally mediated. On four different experiment days, the following
combinations of methacholine and histamine inhalation challenges were performed in 15
subjects (nine normal and six asthmatic) in a random fashion: methacholine-histamine,
histamine-methacholine; methacholine-methacholine and histamine-histamine. Cumulative …