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Intraepithelial Nerve Fibers Project Into the Lumen of the Larynx
Author(s) -
LimaRodrigues Manuel,
Nunes Rui,
Almeida Armando
Publication year - 2004
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200406000-00022
Subject(s) - larynx , anatomy , lamina propria , pathology , calcitonin gene related peptide , lumen (anatomy) , lingual papilla , substance p , free nerve ending , epithelium , superior laryngeal nerve , sensory system , sensory nerve , biology , calcitonin , tongue , chemistry , medicine , receptor , microbiology and biotechnology , neuropeptide , endocrinology , neuroscience
Objectives/Hypothesis: Studies on the morphology and location of the sensory receptors in the laryngeal mucosa have resulted in insufficient and sometimes conflicting data. In the present study the authors analyzed the distribution and morphology of sensory nerve plexuses and terminal fibers in the laryngeal mucosa of the rat. Study Design: Two groups of Male Wistar rats were used in this laboratory study; the larynx of the first group were used to analyse the sensitive innervation of its epithelium, whereas the larynx of the second group (controls) were tested for the specificity of the antibodies used. Methods: The larynges of the animals were entirely removed after perfusion, and coronal or horizontal sections were immunoprocessed for further randomized analysis of the mucosa. Primary afferents were detected by immunoreaction to two widely recognized markers of sensory nerves, calcitonin gene‐related peptide and substance P, and visualized using diaminobenzidine as a chromogen. Results: The nerve plexuses were more densely distributed in the dorsal half of the vocal folds and in the laryngeal aspect of the epiglottis. Dense networks of fine fibers with many varicosities en passant, immunoreactive for both calcitonin gene‐related peptide and substance P, occurred in the lamina propria and along the epithelial thickness. Calcitonin gene‐related peptide–immunoreactive and substance P–immunoreactive fibers extended across the epithelium and projected to the laryngeal lumen itself, reaching the space between the cilia. Conclusion: The projection of intraepithelial nerve fibers into the lumen of the larynx indicates that in the absence of mucus, nerve endings may be exposed and thus receive direct stimulation from airborne substances. Furthermore, it suggests that the laryngeal mucosa of the rat may constitute an experimental model for studying the direct activation or manipulation of primary afferents at the periphery and neurogenic inflammation.