Células neuroendocrinas en yemas gustativas primordiales / Neuroendocrine cells in primordial taste buds

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.

Ontogeny of taste sense.

Developmental changes in the taste receptors and CNS, in physiological and behavioural patterns in fetus and postnatal animals constitute the ontogeny of taste. Tongue epithelial cells are modified into taste buds only with innervation and are seen to degenerate on denervation. On removal of a portion of the tongue, with its taste buds, the central projections of gustation also atrophy, indicating an interdependence of taste receptors and central areas for their development. Gradual transitions in electrical responses to taste stimuli are shown from fetal to adult stage. While responses to ammonium chloride are marked in early fetus, with advancements in age responses to a wide variety of chemicals are shown. Again, early in the development, fibers responsive to chloride are predominant while at a later stage fibers responsive to sodium increase in number. Behaviourally, human fetus and neonatal mammals showed increased swallowing movements on sweet taste and decreased movements on bitter taste which is somewhat at variance with electrophysiological evidence and reflects on the multimodal involvement of taste cell functional and behavioural dynamics with age.