Journal of Applied Physiology, Vol 71, Issue 6 2460-2468, Copyright © 1991 by American Physiological Society
Nasal glandular secretory response to cholinergic stimulation in humans and guinea pigs
A. Z. Gawin, B. E. Emery, J. N. Baraniuk and M. A. Kaliner
Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
A guinea pig model of nasal secretory responses was developed to assess the
contributions of vascular permeability and glandular secretion responsible
for the production of cholinergically stimulated nasal secretions. The
nasal secretory responses to provocation with saline, methacholine, and
atropine on the ipsilateral (challenged) side and contralateral (reflex)
side were analyzed by measurement of total protein (Lowry method), guinea
pig albumin (enzyme-linked immunosorbent assay), 125I-labeled bovine serum
albumin after intravenous injection, and alkaline phosphatase enzyme
activity in nasal fluid. Alkaline phosphatase was found to be localized to
submucosal glands by zymography. Topical methacholine challenge increased
the secretion of total protein, alkaline phosphatase activity, and albumin
on the ipsilateral challenged side, whereas the percentage of total protein
represented by albumin was not increased. This response was totally
prevented by atropine pretreatment. Serial provocation with methacholine
resulted in progressively reduced amounts of both the total protein and
alkaline phosphatase in secretions. The observation that repeated
challenges produced progressively smaller responses was also examined
employing human nasal provocation. Repeating methacholine (25 mg)
challenges four times at 10-min intervals in six human volunteers revealed
that the initial challenge produced the largest response as reflected in
total protein, albumin, lysozyme, lactoferrin, immunoglobulin (Ig) G, IgA,
and secretory IgA secretion. When the constituents in secretions were
analyzed in relationship to the total protein, the two vascular proteins,
IgG and albumin, demonstrated the greatest decrements with repeated
methacholine challenges. The glandular proteins, lactoferrin, lysozyme, and
secretory IgA, either remained constant or increased in their relative
proportion to total protein. Thus, cholinergic stimulation causes glandular
secretion from both the guinea pig and human nasal mucosa.(ABSTRACT
TRUNCATED AT 250 WORDS)
