Journal of Applied Physiology, Vol 60, Issue 2 376-384, Copyright © 1986 by American Physiological Society
Abnormal pulmonary slowly adapting receptors in canine acrylamide neuropathy
M. I. Hersch, P. M. Satchell, C. E. Sullivan and J. G. McLeod
Slowly adapting lung stretch receptors (SARs) and their vagal afferents are
considered to play an important role in the mediation of numerous
respiratory reflexes. The understanding of such reflexes has been
facilitated by altering the discharge properties of SARs or by preventing
the conduction of SAR-generated impulses to the brain stem. In a number of
naturally occurring diseases of the peripheral nervous system, the vagus
nerve and vagal reflexes are damaged. We have studied the function of SARs
in anesthetized dogs with acrylamide neuropathy, a distal axonopathy that
has been used as a model of naturally occurring neuropathies. There was a
marked increase in threshold and decrease in firing rate of SARs in dogs
with moderate neuropathy. Abnormal SAR discharge patterns were observed,
and there was a depletion of those units innervated by the fastest
conducting vagal afferent fibers in treated animals. Acrylamide induced
degeneration of myelinated fibers in bronchial branches of the vagus nerve.
These abnormalities were partially reversed upon withdrawal of the
neurotoxin. Acrylamide may be a useful agent in the study of vagally
mediated respiratory reflexes. SAR function is likely to be abnormal in
diseases of the peripheral nervous system.
