TRPM 8, ASIC 1, and ASIC 3 localization and expression in the human oropharynx

• Published in: Neurogastroenterology and motility Vol. 30; no. 11
• Main Authors: Alvarez‐Berdugo, D., Rofes, L., Casamitjana, J. F., Enrique, A., Chamizo, J., Viña, C., Pollán, C. M., Clavé, P.
• Format: Journal Article
• Language: English
• Published: 01-11-2018
• ISSN: 1350-1925; 1365-2982
• DOI: 10.1111/nmo.13398

Abstract
Background
Oropharyngeal dysphagia (
OD
) is a prevalent disease with poor prognosis among older people and has no pharmacological treatment. Polymodal sensory receptors like the
TRP
or
ASIC
family receptors are potential targets to treat
OD
.
TRPM
8 agonists and acidic solutions can improve the swallow response in patients with
OD
, but little is known about the expression of
TRPM
8,
ASIC
1, and
ASIC
3 in the human oropharynx. The aim of this study was to assess the expression and localization of
TRPM
8,
ASIC
1, and
ASIC
3 in human samples of the oropharynx to lay the basis for new pharmacological treatments for
OD
.
Methods
Pathology‐free samples from oropharyngeal regions innervated by cranial nerves V,
IX
, and X were obtained during major
ENT
surgery and processed to obtain
mRNA
(20 patients) or to be used in immunohistochemical assays (12 patients).
TRPM
8,
ASIC
1, and
ASIC
3 expression and localization were studied with
RT
‐
qPCR
and fluorescent immunohistochemistry.
Key Results
ASIC
3 was expressed in the 3 regions studied with similar levels and was localized on sensory fibers innervating the mucosa below the basal lamina of all studied regions.
TRPM
8 was also co‐localized on the sensory fibers innervating the mucosa below the basal lamina of all studied regions. In contrast,
ASIC
1 was only found in the nerves innervating the tongue muscular fibers.
Conclusions & Inferences
TRPM
8 and
ASIC
3 are found on submucosal sensory nerves in the human oropharynx. Our study lays the basis to use oropharyngeal
TRPM
8 and
ASIC
3 receptors as therapeutic targets to develop new active pharmacological treatments for
OD
patients.