Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0235290 (bitter taste)
 1,408 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Electron microscopical data regarding methylene blue staining of taste buds in the epithelia of the goldfish lip and the cirumvallate papilla of the mouse tongue after supravital dye application are presented for the first time. The ultrastructural details were compared with the corresponding light microscopical findings. The dye was applied in different concentrations by injection or in crystalline from directly to the surface of the tissues. Both methylene blue and tissue were simultaneously fixed by immersion in a paraformaldehyde-glutaraldehyde solution with the addition of phosphomolybdic acid. The ensuing dye precipitate was further stabilized by ammonium heptamolybdate. On the light microscopical level, the taste bud's receptive structures, i.e. the receptor area (fish) and the taste pit (mouse), exhibited the highest affinity for the dye. Additionally, the mucous material within the trenches around the circumvallate papillae in mice was intensely stained. On the electron microscopical level, the cationic phenothiazine dye bound to the receptor villi or to the mucus coating the receptive structures. In the case of higher dye concentrations, a staining of single taste bud cells took place starting apically and proceeding down to the base. Dye accumulations within the intercellular clefts between the epithelial cells or within other structures were observed only if the dye concentration was further increased. Since similar results were also obtained with the cationic phenazo dye Janus green, dye accumulation in the mucus covering the receptor villi may be representative of the general binding of organic cations, which are known to induce bitter taste sensations.
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PMID:Light and electron microscopical demonstration of methylene blue accumulation sites in taste buds of fish and mouse after supravital dye injection. 875 Nov 11

The sense of taste provides animals with valuable information about the nature and quality of food. Bitter taste detection functions as an important sensory input to warn against the ingestion of toxic and noxious substances. T2Rs are a family of approximately 30 highly divergent G-protein-coupled receptors (GPCRs) that are selectively expressed in the tongue and palate epithelium and are implicated in bitter taste sensing. Here we demonstrate, using a combination of genetic, behavioural and physiological studies, that T2R receptors are necessary and sufficient for the detection and perception of bitter compounds, and show that differences in T2Rs between species (human and mouse) can determine the selectivity of bitter taste responses. In addition, we show that mice engineered to express a bitter taste receptor in 'sweet cells' become strongly attracted to its cognate bitter tastants, whereas expression of the same receptor (or even a novel GPCR) in T2R-expressing cells resulted in mice that are averse to the respective compounds. Together these results illustrate the fundamental principle of bitter taste coding at the periphery: dedicated cells act as broadly tuned bitter sensors that are wired to mediate behavioural aversion.
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PMID:The receptors and coding logic for bitter taste. 1575 3