Localization of TRP Channels in Healthy Oral Mucosa from Human Donors.

The oral cavity is exposed to a remarkable range of noxious and innocuous conditions, including temperature fluctuations, mechanical forces, inflammation, and environmental and endogenous chemicals. How such changes in the oral environment are sensed is not completely understood. Transient receptor potential (TRP) ion channels are a diverse family of molecular receptors that are activated by chemicals, temperature changes, and tissue damage. In non-neuronal cells, TRP channels play roles in inflammation, tissue development, and maintenance. In somatosensory neurons, TRP channels mediate nociception, thermosensation, and chemosensation. To assess whether TRP channels might be involved in environmental sensing in the human oral cavity, we investigated their distribution in human tongue and hard palate biopsies. TRPV3 and TRPV4 were expressed in epithelial cells with inverse expression patterns where they likely contribute to epithelial development and integrity. TRPA1 immunoreactivity was present in fibroblasts, immune cells, and neuronal afferents, consistent with known roles of TRPA1 in sensory transduction and response to damage and inflammation. TRPM8 immunoreactivity was found in lamina propria and neuronal subpopulations including within the end bulbs of Krause, consistent with a role in thermal sensation. TRPV1 immunoreactivity was identified in intraepithelial nerve fibers and end bulbs of Krause, consistent with roles in nociception and thermosensation. TRPM8 and TRPV1 immunoreactivity in end bulbs of Krause suggest that these structures contain a variety of neuronal afferents, including those that mediate nociception, thermosensation, and mechanotransduction. Collectively, these studies support the role of TRP channels in oral environmental surveillance and response.

Somatosensory innervation of healthy human oral tissues.

The oral somatosensory system relays essential information about mechanical stimuli to enable oral functions such as feeding and speech. The neurochemical and anatomical diversity of sensory neurons across oral cavity sites have not been systematically compared. To address this gap, we analyzed healthy human tongue and hard-palate innervation. Biopsies were collected from 12 volunteers and underwent fluorescent immunohistochemistry (≥2 specimens per marker/structure). Afferents were analyzed for markers of neurons (ßIII tubulin), myelinated afferents (neurofilament heavy, NFH), and Merkel cells and taste cells (keratin 20, K20). Hard-palate innervation included Meissner corpuscles, glomerular endings, Merkel cell-neurite complexes, and free nerve endings. The organization of these somatosensory endings is reminiscent of fingertips, suggesting that the hard palate is equipped with a rich repertoire of sensory neurons for pressure sensing and spatial localization of mechanical inputs, which are essential for speech production and feeding. Likewise, the tongue is innervated by afferents that impart it with exquisite acuity and detection of moving stimuli that support flavor construction and speech. Filiform papillae contained end bulbs of Krause, as well as endings that have not been previously reported, including subepithelial neuronal densities, and NFH+ neurons innervating basal epithelia. Fungiform papillae had Meissner corpuscles and densities of NFH+ intraepithelial neurons surrounding taste buds. The differing compositions of sensory endings within filiform and fungiform papillae suggest that these structures have distinct roles in mechanosensation. Collectively, this study has identified previously undescribed neuronal endings in human oral tissues and provides an anatomical framework for understanding oral mechanosensory functions.

Lingual cyst with respiratory epithelium: report of 2 cases and review of the literature.

The lingual cyst with respiratory epithelium, a congenital cyst of the tongue or floor of the mouth, is lined predominately by respiratory-type epithelium. The terminology for this lesion was first proposed in 1999 by Manor et al., who stated that a descriptive term is best for this cyst of debatable pathogenesis. Although it is a cyst of foregut origin, the lingual cyst with respiratory epithelium is distinguished from the traditional enteric (foregut) duplication cyst in that the latter contains gastric and/or intestinal-type mucosa and has smooth muscle within the cyst wall. This article presents 2 new cases of this entity, as well as reviews the 19 cases that have been reported in the literature and were found to fulfill the histologic criteria of an lingual cyst with respiratory epithelium.

Association of symptoms and convergence and accommodative insufficiency in school-age children.

BACKGROUND: The purpose of this article was to investigate the association between convergence insufficiency (CI) and accommodative insufficiency (AI) and symptoms in a group of school-aged children. METHODS: Children ages 8 to 15 years were recruited from two public and 2 private elementary schools in Southern California. The CI Symptom Survey (CISS) was administered to all children before a Modified Clinical Technique vision screening. Children with normal visual acuity, minimal uncorrected refractive error, and no strabismus were tested for CI and Al. RESULTS: Four hundred sixty nine children were initially screened and 392 participated in testing for CI and AI. Fifty-five percent of the children (218) were classified as having normal binocular vision (NBV), 4.6% (18) had three signs of CI, 12.7% (50) had two signs of CI, 10.5% (41) were classified as AI (with no signs of CI), and 16.6% (65) were classified as other. The symptom score was 3.78 for the NBV group, 4.6 for the two-sign CI group, 6.67 for the three-sign CI group, and 6.37 for the Al group. The three-sign CI and the Al groups scored significantly higher than the NBV group on the CISS (p < or = 0.001). CONCLUSION: CI and AI are common conditions in school-age children and are associated with increased symptoms.