Permeability of Oral Mucosa

Abstract

ABSTRACT:In discussing permeability, we are describing one of the fundamental barrier functions of oral mucosa. Despite assumptions to the contrary, the oral mucosa is not a uniformly, highly permeable tissue like gut, but shows regional variation. The keratinized areas, such as gingiva and hard palate, are least permeable and nonkeratinized lining areas are most permeable. This variation appears to reflect differences in the types of lipid making up the intercellular permeability barrier in the superficial layers of the epithelium. Differences in permeability may be related to regional differences in the prevalence of certain mucosal diseases and can be utilized to advantage for local and systemic drug delivery.

Multisensory Processing of Gustatory Stimuli

“…However, due to their low permeability through stratified epithelia (Squier 1973;Squier and Johnson 1975), such compounds are unlikely to directly activate mechanoreceptors, thermoreceptors, or nociceptors embedded in the epithelium or papillary layer. In contrast, more hydrophobic compounds such as alcohols-like ethanol-or alkaloids that interact with bitter-responsive T2R receptors on taste cells (Chrandrashekar et al 2000) not only have the potential to activate taste cells and their associated nerves but also to diffuse into the epithelium (Mistretta 1971) and activate somatosensory nerve terminals.…”

Starch digestion in the upper gastrointestinal tract of humans

“…In the oral cavity, sweet compounds which indicate the presence of carbohydrates such as glucose are detected by the taste receptors present in taste buds. Taste buds are located around the lingual papillae on the dorsal surface of the tongue, the soft muscular palate located at the back roof of the mouth, the cheek and the upper oesophagus . Taste receptors belong to the to the G protein coupled receptor (GPCR) family of proteins.…”

“…Taste receptors belong to the to the G protein coupled receptor (GPCR) family of proteins. In humans, the binding of glucose activates the TAS1R2 and TAS1R3 receptors in the taste buds, resulting in a cascade of intracellular pathways involving different subunits of the GPCR leading to the release of ATP . This cascade mechanism leads to the accumulation of calcium ions in the cytoplasm, and insulin secretion .…”

Sublingual vaccination with fusion protein consisting of the functional domain of hemagglutinin A of Porphyromonas gingivalis and Escherichia coli maltose-binding protein elicits protective immunity in the oral cavity

“…Finally, sublingual vaccines require much less of the antigen than is required for intragastric vaccination. Also, sublingual mucosa have been proposed to be more permeable to low‐molecular‐weight drugs (Zhang et al ., ) and small immunogenic peptides than the cheek mucosa (Squier, ), a general oral mucosa that contains dendritic cells (DCs). DCs take up foreign antigens in the submucosal region, which migrate to the regional lymph nodes, where the antigen is presented to T‐lymphocytes by DCs to activate the adaptive immune responses (Song et al ., ).…”