Journal of Applied Physiology, Vol 53, Issue 3 690-697, Copyright © 1982 by American Physiological Society
Effect of aerosolized histamine on occlusion pressure and ventilation in humans
R. P. Millman, D. A. Silage, D. D. Peterson and A. I. Pack
To define further the mechanism by which inspiratory neural activity is
increased in asthma, we studied the effect of aerosolized histamine on
occlusion pressure (P100) and ventilation in conscious humans while
end-tidal CO2 partial pressure was maintained at a constant, slightly
hypercapnic level. The dose of histamine we employed varied from subject to
subject but was such that it produced a 70% reduction in specific airway
conductance in each subject. In 9 of the 13 subjects tested, inhaled
histamine significantly increased P100. This increase was not due to
changes in functional residual capacity, which was not affected by
aerosolized histamine. Inhalation of isoproterenol abolished the effects of
histamine on specific airway conductance and P100. Anesthesia of the
airways by lidocaine eliminated the effect of histamine on P100 but did not
alter the magnitude of the change in specific airway conductance produced
by histamine. We conclude that the increase in occlusion pressure seen
after the inhalation of histamine in humans depends on both contraction of
bronchial smooth muscle and stimulation of airway receptors.
