Journal of Applied Physiology, Vol 42, Issue 2 221-227, Copyright © 1977 by American Physiological Society
Effects of intravenous histamine on pulmonary mechanics in nonasthmatic and asthmatic subjects
R. Brown, R. H. Ingram Jr, J. J. Wellman and E. R. McFadden Jr
Histamine is thought to be one of the primary mediators of the airways
response in allergic asthma. We have studied in detail in nonasthmatic and
asthmatic volunteers the effects of its intravenous infusion on pulmonary
mechanics. The doses used were similar in both groups and limited by
vascular rather than pulmonary effects. Measurements were made of lung
resistance, the subdivisions of lung volume, maximal flow, density
dependence, lung elastic recoil and dynamic compliance. The only mean group
changes were a decrease in dynamic compliance and increase in frequency
dependence of compliance in the nonasthmatics. Although in nonasthmatic
individuals, statistically significant changes occasionally occurred in
some parameters, the response was variable on repeated studies and
sufficiently small to be of questionable physiological significance. Some
of the asthmatics developed larger changes, but these only occurred in
those individuals whose preinfusion pulmonary function was abnormal. Our
results suggest the possibility that altered prechallenge pulmonary
function rather than an unusual sensitivity to histamine may determine the
greater responses observed in asthmatics.
