Localization and expression of TRPV1 and TRPA1 in the human oropharynx and larynx. Issue 1 (4th November 2015)

• Record Type: Journal Article
• Authors: Alvarez‐Berdugo, D.; Rofes, L.; Farré, R.; Casamitjana, J. F.; Enrique, A.; Chamizo, J.; Padrón, A.; Navarro, X.; Clavé, P.
• Is Part Of: Neurogastroenterology & motility. Volume 28:Issue 1(2016)
• Page Start: 91
• Page End: 100
• Publication Date: 2015-11-04
• Subjects: Ankyrin‐like with transmembrane domains protein 1 -- oropharyngeal dysphagia -- sensory input -- vanilloid receptor 1; Gastrointestinal system -- Motility -- Periodicals; Gastrointestinal system -- Innervation -- Periodicals; 616.33
• DOI: 10.1111/nmo.12701
• Languages: English
• ISSNs: 1350-1925

Abstract

Abstract: Background: Previous studies have found that TRPV1 and TRPA1 receptor agonists improve swallow response in patients with oropharyngeal dysphagia (OD), but little is known about the expression of these receptors in the human oropharynx. The aim of this study was to assess the expression and localization of TRPV1 and TRPA1 in human samples from the oropharynx of healthy patients, to provide the basis for new pharmacological treatments for OD. Methods: Samples from oropharyngeal regions innervated by cranial nerves V, IX, and X (tongue, pharynx, and epiglottis) were obtained during ENT surgery and processed either for mRNA (21 patients) or for immunohistochemical assays (seven patients). The expression analysis was performed with RT‐qPCR using ACTBh as reference gene. Hemotoxylin and eosin staining was used to study the histology; the immunohistochemical assay used (i) neuron‐specific enolase to detect nerve fibers or (ii) fluorescent probes to locate TRPV1 and TRPA1. Results: TRPV1 was expressed in the three studied regions, with higher levels in CN V region (tongue) than in CN X region (epiglottis; p < 0.05), and was localized at epithelial cells and nociceptive fibers in all studied regions. TRPA1 was also expressed in all studied regions, but was always localized below the basal lamina. No immunoreactivity for TRPA1 was found on epithelial cells. Conclusions & Inferences: TRPV1 and TRPA1 are widely expressed in the human oropharynx with two distinct patterns. Our study further confirms that TRPV1/A1 receptors are promising therapeutic targets to develop active treatments for OD patients. Abstract : Previous studies have provided supportive evidence to suggest that TRPV1 and TRPA1 agonists improve swallow response on neurogenic OD patients, but little is known about the expression and localization of these receptors in the oropharynx. This study explores the expression and localization of TRPV1 and TRPA1 in human oropharyngeal samples with RT‐qPCR and fluorescent immunohistochemistry. TRPV1 and TPRA1 expression is found throughout the oropharynx and these receptors are immunolocalized with two specific patterns. TRPV1 is found on epithelial cells and submucosal sensory nerves, whereas TRPA1 is only found below the basal lamina. Oropharyngeal TRPV1/A1 receptors are promising therapeutic targets to develop active treatments for OD patients.