In situ visualization of bronchial submucosal glands and their
secretory response to acetylcholine.
Inglis, Sarah K., Michel R. Corboz, Aubrey E. Taylor, and Stephen T.
Ballard.
Department of Physiology, College of Medicine, University of South
Alabama, Mobile, AL 36688
APStracts 3:0174L, 1996.
Airway submucosal glands secrete both macromolecules and liquid, yet
the mechanisms by which these substances are secreted are not well
understood. In this study, a videomicroscope was used to directly
visualize the submucosal glands in isolated porcine distal bronchi
and to observe their responses to acetylcholine (ACh), a glandular
secretagogue. Submucosal glands were classified either as
"antral," "linear," or "convoluted"
glands based on the morphology of their terminal collecting ducts.
Because antral duct glands were most easily visualized, the response
to ACh was studied in detail in this gland type. Within 5-10s after
addition of 10 M ACh, the cross-sectional area of the gland duct
openings to the airway surface increased several fold but returned to
pre-ACh dimensions within 1min. Between 30s and 10min following ACh
addition, spherical particles (1-10 m) entered the antral ducts from
distal acini and exited through the duct openings to the airway
surface. Some of the particles were retained within the antral duct
where they were kept in constant motion by the action of cilia
present within the antral duct. The particles, which are likely to
contain the macromolecular secretory products of mucous and/or serous
cells, maintained their spherical shape within the gland duct
suggesting that the secretion product was membrane bound. To our
knowledge, these studies provide the first description of airway
submucosal gland secretion as viewed in situ.
Received 9 February 1996; accepted in final form 23 September
1996.
APS Manuscript Number L45-6.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 November 1996