Journal of Applied Physiology, Vol 58, Issue 1 27-33, Copyright © 1985 by American Physiological Society
Acute effects of cigarette smoke inhalation on peripheral airways in dogs
M. Nakamura, T. Haga, H. Sasaki and T. Takishima
We studied the acute effects of the inhalation of cigarette smoke on the
central and peripheral airways of 35 open-chested and tracheotomized dogs
by the direct measurement of central (Rc) and peripheral (Rp) airway
resistances. Rc was calculated by dividing the pressure difference between
a tracheal catheter and a retrograde catheter by mouth flow, and Rp was
obtained by dividing the pressure difference between the retrograde
catheter and a pleural capsule by mouth flow. The pleural capsule was
attached to the pleural surface for alveolar pressure measurement. Rc and
Rp were measured by the 2-Hz forced oscillation method. With lung
inhalation of the smoke of two-thirds of one cigarette in vagi intact dogs,
Rp increased to 239% of the control value and Rc increased to 112%. After
bilateral vagotomy, Rp increased to 143% and Rc increased to 104%.
Propranolol did not influence the results. Hexamethonium and atropine both
blocked these responses when vagi were intact. When the upper trachea,
larynx, and nasopharynx, which were completely blocked by vagotomy, were
exposed to the smoke of two-thirds of a cigarette, Rp increased to 155% and
Rc increased to 144%. We thus conclude that cigarette smoke causes a major
increase in Rp, mainly via the vagal reflex and partially via the
stimulation of parasympathetic ganglia (probably nicotine), and a minor
increase in Rc via vagal reflex.
