RT Journal Article SR Electronic T1 Bronchial responsiveness to inhaled histamine and isoprenaline in patients with airway obstruction. JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 211 OP 213 DO 10.1136/thx.33.2.211 VO 33 IS 2 A1 Benson, M K YR 1978 UL http://thorax.bmj.com/content/33/2/211.abstract AB In order to examine the hypothesis that bronchial reactivity to non-specific constrictor stimuli is influenced by the resting tone of the bronchial smooth muscle, the airway responses to inhaled histamine solution and inhaled isoprenaline were measured in 19 patients with airway obstruction. There was a significant positive correlation between the size of the constrictor response to histamine and the dilator response to isoprenaline (r = +0.83; p less than 0.01) as measured by changes in specific airway conductance. Patients with asthma showed greater bronchial reactivity to both histamine and isoprenaline than those with chronic bronchitis, although some patients had changes intermediate between the two extremes.