Journal of Applied Physiology, Vol 57, Issue 4 1079-1088, Copyright © 1984 by American Physiological Society
Local vagal responses in the lung periphery
A. Gertner, B. Bromberger-Barnea, L. Kelly, R. Traystman and H. Menkes
In previous work we studied responses to ozone (O3) in the lung periphery
of anesthetized male mongrel dogs. O3 (0.1 ppm) delivered locally to the
lung periphery through a bronchoscope wedged in a segmental airway
increased collateral resistance (Rcs) 31.5 +/- 5%. Bilateral cervical
vagotomy or pretreatment with atropine aerosol prevented these responses to
O3. In the present study we asked two questions. First, is the vagus
necessary for responses to 0.1 ppm O3 because it maintains base-line tone?
Second, are physiological responses to O3 administered through a
bronchoscope localized to the challenged region? To answer the first
question, we increased base-line Rcs (38.4 +/- 11.8%) by administering an
acetylcholinesterase inhibitor, neostigmine (aerosol), through the
bronchoscope. Following neostigmine, O3 exposure increased Rcs (55.8 +/-
18.4%) only if the vagi were intact. To answer the second question, we
introduced two bronchoscopes simultaneously into different regions of the
lung. When O3 was delivered through one bronchoscope, responses were
detected only in the exposed region. However, when the whole left lung was
exposed to O3, the responses were also detected in the right lung, but only
when the vagi were intact. We conclude that the lung has the capacity to
respond to localized oxidant insult with vagally mediated responses limited
to the region that is challenged. However, when a larger area is exposed,
vagally mediated responses become generalized and affect both lungs.
