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The tayra (Eira barbara) is a mammal belonging to the Mustelidae family that occurs in all Brazilian biomes. The present work aimed to describe the morphology of the tongue of these specimens highlighting their structures and particularities that will serve as a subsidy to elucidate the anatomy of the same and for comparative studies among other species of domestic and wild animals. Five adult male specimens of E. barbara were studied, which were fixed using 10% aqueous formaldehyde solution. The tongue was removed by opening the oral cavity and separating the maxillary/mandible bone complex. Being in possession of the material, photodocumentations and collection of the fragments were made for the proper preparation of histological slides and Scanning Electron Microscopy (SEM). The lingual papillae found in tayra were mechanical: filiform and conical; and gustative: fungiform and circumvallated. Histologically, the papillae are constituted by keratinized stratified epithelium and in the innermost region, it was composed of tissue connective dense unshaped followed by a layer of muscle bundles of skeletal striated. In the region of the root of the tongue of E. barbara, there were a set of small mixed salivary glands (serous and mucous) and the punctual presence of gustatory corpuscles at the level of epithelium. The morphological description of the E. barbara tongue revealed similarity to that described in literature for other domestic and wild mammals. However, the particularity of the absence of foliate papilla and the quantitative of four papillae circumvallate in the region of the root of the tongue of this species.

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El objetivo del trabajo fue identificar la presencia de células neuroendócrinas en yemas gustativas primordiales (fetales) humanas. Fueron utilizadas 15 lenguas fetales humanas obtenidas de abortos espontáneos (tiempo de gestación 23 semanas) de pacientes ingresados en el Hospital General, Chihuahua, México. Una muestra representativa del ápex lingual fue embebida en parafina y cortada a 3 micras para ser procesadas con la técnica inmunohitoquímica utilizando los siguientes anticuerpos: Anti-sinaptofisina; anti-proteína neurofilamento; anti-cromogranina; anti-citoqueratina 20; y anti proteínas-S100. El protocolo de investigación fue aprobado por los comités de bioética de las instituciones participantes. Se obtuvo la autorización de los padres para la utilización del material biológico. Las células gustativas fetales fueron fuertemente positivas a cromogranina, y negativas a sinaptofisina. Las papilas gustativas fetales humanas mostraron inmunorreactividad positiva contra citoqueratina 20, mientras que fibras nerviosas intragemulares mostraron inmunorreactividad contra anticuerpos anti-proteína neurofilamento. Las fibras nerviosas subyacentes al epitelio gustativo fueron positivas a proteína S100. Se muestra evidencia inmunohistoquímica de la presencia de células neuroendócrinas gustativa en yemas gustativas linguales primordiales humanas. Esto sugiere una probable participación neuroendocrina o paracrina en el desarrollo de las yemas gustativas humanas.

The objective was to identify the presence of neuroendocrine cells in primary taste buds (fetal) cells. We used 15 human embryionic fetal tongues derived from human spontaneous abortions (23 weeks gestation time) of patients admitted to the General Hospital, Chihuahua Mexico. A representative sample of lingual apex was embedded in paraffin and cut to 3 microns processed by immune histochemical technique using the following antibodies: anti-synaptophysin, neuro filament anti-protein, anti chromogranin; anti-citokeratin 20 and S100 anti proteins. Research was approved by bioethics committees of the participating institutions. Permission was obtained from the parents to use the biological material. The taste bud fetal cells were significantly positive for chromogranin and synaptophysin negative. The human fetal taste buds showed positive immunoreactivity against cyto keratin 20, while nerve fibers underlying the gustatory epithelium were positive for S100 protein. Immunohistochemical evidence shows the presence of neuro endocrine cells in human primordial taste bud papilla. This suggests a probable neuro endocrine or paracrine participation in the development of human taste buds.

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The distribution pattern of taste buds and goblet cells and histochemical and ultrastructural aspects of the tongue epithelium of Ambystoma mexicanum are here described. This study is also concerned with the developmental stages and origins of the epithelial cells. Pavement cells and goblet cells of the stratum superficiale are replaced by basal cells of the stratum germinativum in larvae and neotenous adults. The pavement cells of the larvae are characterized by a marginal layer of mucin grana. Decompaction of the mucins occurs immediately before extrusion in the adult. The larval goblet cell type (type I), which is also present in the adult, contains unfused grana of irregular shape. At the tip of the tongue, a further type (type II) of goblet cells is found. In the type II cells the intracellular secretory grana fuse to a single homogeneous mass. Leydig cells of the tongue epithelium are discerned by light microscopy first in the semi-adult, apparently correlated with partial metamorphosis. In the course of ontogenesis and induced metamorphosis the secretion changes to neutral glycoconjugates. The mucins of the pavement cells change first followed by those of the goblet cells. The glands of the secondary tongue show a dorso-ventral pattern of varying secretory qualities. Taste buds are found at the anterior margin of the tongue and along the base of the gill clasps in the early larva. They are already distributed all over the tongue at the end of the early larval phase.

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