Expression of vasoactive intestinal peptide, calcitonin gene-related peptide, substance P, and intermediate neurofilaments in nasal mucosal nerve fibers of horses without nasal disease.
OBJECTIVE
To determine the distribution of nerve fibers containing calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP), and intermediate neurofilaments in nasal mucosa of horses.


METHODS
6 horses without evidence of nasal disease.


METHODS
Full-thickness nasal tissue specimens were obtained from the rostral portion of the nasal septum at necropsy, and fluorescence immunohistochemistry was performed to assess mucosal distribution of nerve fibers.


RESULTS
Nerve fibers with CGRP-like immunoreactivity (CGRP-Li) formed a dense subepithelial network, and a large number of fibers were found coursing between epithelial cells. Fibers with CGRP-Li were also associated with blood vessels and mucous glands. Fibers with SP-like immunoreactivity (SP-Li) had a similar distribution and density. In contrast, there were few fibers with VIP-like immunoreactivity. Fibers containing intermediate neurofilaments were prominent and appeared as large nerve fiber bundles mainly adjacent to the nasal septum but also close to mucous glands and within the lamina propria. Intermediate neurofilaments were also identified in single nerve fibers at all sites, but the density of fibers with intermediate neurofilaments did not match that of fibers with CGRP- or SP-Li.


CONCLUSIONS
The density and distribution of nerve fibers containing SP- or CGRP-Li in nasal mucosa of horses was similar to that reported for other species. However, expression of VIP in nerve fibers was low. Antibodies against intermediate neurofilaments identified many nerve fibers in nasal mucosa of horses but did not appear to identify small diameter fibers expressing SP or VIP.
Corcoran
B M
BM
Department of Veterinary Clinical Studies, Royal Dick School of Veterinary Studies, The University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian, Scotland.
Mayhew
I G
IG
Hahn
C N
CN
Prince
D R
DR
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis*; D006736:Horses; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000032:analysis*; D007382:Intermediate Filaments / Q000648:ultrastructure; D009297:Nasal Mucosa / Q000166:cytology / Q000294:innervation*; D009300:Nasal Septum; D009412:Nerve Fibers / Q000648:ultrastructure*; D012016:Reference Values; D013373:Substance P / Q000032:analysis*; D014660:Vasoactive Intestinal Peptide / Q000032:analysis*
D007381:Intermediate Filament Proteins; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D015740:Calcitonin Gene-Related Peptide