Journal of Applied Physiology, Vol 57, Issue 1 278-283, Copyright © 1984 by American Physiological Society
Maintenance of muscarinic tone after vagotomy in the lung periphery
A. Gertner, B. Bromberger-Barnea, R. Traystman and H. Menkes
We developed a method for maintaining muscarinic tone in a small region of
the lung periphery after vagotomy. A fiber-optic bronchoscope was wedged in
a segmental airway of anesthetized male mongrel dogs and was used to
deliver aerosols of distilled water (0.1 ml), neostigmine (0.022 mg),
atropine (0.1 mg), and histamine (1.5 X 10(-4) mg). Measurements of
resistance through the collateral system (Rcs) were used to monitor
responses to these agents. Rcs increased 37.0 +/- 5.0% (mean +/- SE) after
the administration of neostigmine and remained elevated for at least 50
min. The administration of neostigmine in vagotomized animals or in those
where the obstructed lung segment was pretreated with atropine resulted in
a small increase in Rcs that lasted only 2 min. When bilateral vagotomy was
performed 10 min after neostigmine administration Rcs remained elevated for
at least another 80 min. However, Rcs returned to baseline when atropine
was administered 20 min after vagotomy, but increased when histamine was
administered 50 min after atropine. We conclude that after neostigmine
administration, parasympathetic tone, dependent on mediators released from
the vagus nerve, can be maintained in the lung periphery after vagotomy.
