Effects of organotypic culture on the parasympathetic innervation
of guinea pig trachealis.
Canning, Brendan J., Bradley J. Undem, Petros C. Karakousis, and
Richard D. Dey.
The Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview
Circle, Baltimore, MD 21224 and West Virginia University, Department
of Anatomy, Health Sciences North, P.O. Box 9128, Morgantown, WV
26506-9128
APStracts 3:0116L, 1996.
Nonadrenergic, noncholinergic (NANC) relaxations of airway smooth
muscle are thought to be mediated by vasoactive intestinal peptide
(VIP) and nitric oxide (NO). Previous studies of the parasympathetic
innervation of guinea pig trachealis suggest that the ganglion
neurons mediating NANC relaxations, but not cholinergic contractions,
are associated with the esophagus. In this study the location of the
neurons mediating these responses and their neurochemical phenotype
was further assessed. Guinea pig tracheas maintained in organotypic
culture for 2 days with the adjacent esophagus intact displayed
cholinergic contractions and NANC relaxations to EFS and VIP and NO
synthase (NOS) nerve fiber densities that were similar to those of
control tracheas. By contrast, NANC relaxations to EFS were not
observed and VIP and NOS nerve fiber densities were reduced more than
80% in tracheas cultured without the esophagus. EFS-induced
cholinergic contractions were unaffected by esophagus removal. These
results provide further evidence that NANC relaxations are mediated
by VIP and NO coreleased from noncholinergic parasympathetic nerve
endings derived from neurons intrinsic to the esophagus.
Received 26 March 1996; accepted in final form 24 June 1996.
APS Manuscript Number L96-6.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996