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The blackspot seabream (Pagellus bogaraveo, Brünnich, 1768) is an omnivorous, predominantly carnivorous fish. In aquaculture, it is fed with pellets rich in proteins and fat. The morphological and functional aspects of the fish tongue, the feeding modality and the tasting capacity are strictly related. Therefore, the aim of this study was to describe by scanning electron, light and confocal laser microscopy, the morphological characteristics of the tongue in this species. It showed an apex, a body and a root. There were rows of teeth on the edges of the mouth and taste pores on all the tongue dorsal surface with folds and furrows. In addition, body and root showed several fungiform-like papillae in the mucosa of the folds, covered by a weakly keratinized stratified squamous epithelium, can be observed. The papillae were innervated by S100 positive fibres. In the apex, a mesenchymal tissue with vimentin positive star-shaped stem cells was evident. The results could give a support for a wider use of the blackspot seabream as a farmed species, considering the morphological data as correlated with the potentiality of food discrimination. This provides a basis for possible applications in feeding strategies. The presence, localization and characteristics of the mesenchymal stem cells, as seen also in previous studies, could represent a further basis for future applications in clinical trials., (© 2021 The Authors. Anatomia, Histologia, Embryologia published by Wiley-VCH GmbH.)

The rainbow trout (Oncorhynchus mykiss Walbaum, 1792) is a fish commercially farmed all over the world. These fish are usually fed, in aquaculture, with pellets rich in proteins and fat. It is well known that there are close relationships among the adaptation of vertebrates to their environment, the capacity and the modality of feeding and the oral cavity morphology, especially the tongue one. No data are so far available about the morphology of the rainbow trout tongue, and therefore, the aim of this study was to investigate by light, scanning electron and confocal laser microscopy, the morphological characteristics of the tongue. An apex, a body and a root can be distinguished in the tongue, and the presence of teeth, taste buds and fungiform-like papillae was demonstrated. Light microscopy shows the presence of an adipose tissue pad in the deeper layer of the apex and in the most superficial layer of the root. In the deeper layer of the body, a triangular-shaped pad consisting of fusiform cells immersed in abundant extracellular matrix of the mesenchymal tissue was observed. The confocal laser microscopy shows the presence of cells with a fibroblast-like morphology positive for vimentin. In the deepest layer of the tongue root, a large area of osteo-cartilaginous tissue was observed. The results, besides the description of the morphological characteristics of the tongue, related to studies regarding the feeding, could be considered for the eventual applications of the use of mesenchymal cells, observed in adult fish, in cell therapies in different pathologies., (© 2020 Wiley-VCH GmbH.)

The Atlantic salmon (Salmo salar) is a freshwater and marine fish of the family Salmonidae, widely farmed in aquaculture facilities in several countries. The salmon are carnivorous, but in aquaculture, alternative foods have been experienced. It is well known that feeding in captivity should cause adaptation and modifications of the morphological characteristics of the oral cavity, especially of tongue; therefore, the aim of this study was to investigate, by light, laser confocal and scanning electron microscopy, the morphological characteristics of the tongue dorsal surface, considering the importance of the correlations between feeding habits and the anatomy of the tongue. Scanning electron microscopy demonstrates the presence of caniniform teeth with oro-aboral orientation surrounded by numerous filiform papillae, single, fused or arranged in row. Oro-aborally, the papillae show an appearance like a rosette and they disappear at level of the root. Light and laser confocal microscopy demonstrates that the mucosa is covered by a non-keratinized stratified pavement epithelium with, in the deepest layer, the presence of a triangular structure whose apex is cranially directed and base facing aborally. In this structure, spindle-shaped cells are present, with a vimentin immunoreactivity, that for their characteristics could be adult mesenchymal stem cells. The obtained data could be useful not only for further studies on the nutrition, but it is interesting the detection of tissues typical of the embryo-fetal phase in the adult specimens tongue, thus giving a basis for studies of potential applications, if any, regarding cell therapies for different clinical indications., (© 2020 Wiley-VCH GmbH.)

The leopard gecko is a crepuscular and insectivorous reptile. The role of the tongue in this reptile is fundamental for the prey capture and ingestion and is not related with eyes cleaning as usual in other geckos. The elongated tongue can be divided into a foretongue with a slightly bifurcated apex and a hindtongue. Scanning electron microscopy demonstrated that several different papillae are present on the dorsal surface, foliate and dome-shaped in the foretongue, becoming thicker and stouter with reduced interpapillary spaces in the lateral parts. The hindtongue is characterised by wide foliate papillae with indented margins and deep fissures of the mucosa. Light microscopy showed the presence of a stratified slightly keratinized squamous epithelium in the apex of the foretongue, a stratified non-keratinized squamous epithelium in the fore and in the hindtongue. In the foretongue, numerous muciparous caliciform cells were observed. Moreover, the presence of taste buds on the tongue ventral surface was demonstrated for the first time in this species and the confocal laser study revealed a strong immunoreactivity for the S-100 protein in the sensory cells. Therefore, the results obtained could give a contribution to the knowledge of the tongue anatomy and are a basis for eventual further studies regarding the feeding habits in a reptile become a popular pet., (© 2019 Blackwell Verlag GmbH.)

Leptin is an anorectic hormone secreted mainly by peripheral adipocytes but also by other central and peripheral tissues. It acts by means of a receptor called OB-R, influencing not only appetite and body mass but being also involved in many fields like endocrinology, metabolism and reproduction. Immunohistochemistry and qRT-PCR techniques were, respectively, used to demonstrate the presence of leptin and its receptor in the gut of adult zebrafish and to evaluate the leptin gene expression response to feeding and fasting. Immunoreactivity for the antibodies utilized was demonstrated in feeding but not in fasting fish, and the gene expression analysis corroborates the data obtained by immunohistochemistry. Therefore, all the obtained results support the hypothesis of the role of this hormone in food regulation in zebrafish., (© 2018 Blackwell Verlag GmbH.)

The mechanosensory lateral line system of fish is responsible for several functions such as balance, hearing, and orientation in water flow and is formed by neuromast receptor organs distributed on head, trunk and tail. Superficial and canal neuromasts can be distinguished for localization and morphological differences. Several information is present regarding the superficial neuromasts of zebrafish and other teleosts especially during larval and juvenile stages, while not as numerous data are so far available about the ultrastructural characteristics of the canal neuromasts in adult zebrafish. Therefore, the aim of this study was to investigate by transmission electron microscopy the ultrastructural aspects of cells present in the canal neuromasts. Besides the typical cellular aspects of the neuromast, different cellular types of hair cells were observed that could be identified as developing hair cells during the physiological turnover. The knowledge of the observed cellular types of the canal neuromasts and their origin could give a contribution to studies carried out on adult zebrafish used as model in neurological and non-neurological damages, such as deafness and vestibular disorders., (© 2018 Blackwell Verlag GmbH.)

The zebrafish is a common model for developmental studies including those regarding tooth, palate and tongue. Nevertheless, little information is available about the morphology of the oral cavity in this teleost, especially in adult animals. In this study we used light, scanning and transmission electron microscopy to describe in detail the morphology of the oral cavity of adult zebrafish. The oral cavity could be divided into three different zones: the outer containing the lips, the intermediate corresponding to the internal valves and the internal that corresponds to the tongue. In the upper and lower intermediate zones, there were semilunar shaped valves, more prominent in the upper part. The internal lower zones correspond to the palate and the tongue, which is an individualized structure filled with numerous transversal ridges. Both the intermediate and internal zones were covered by a stratified epithelium containing numerous mucous and rodlet cells. Present data provide the first description of the morphology and structure of the oral cavity in the adult zebrafish and might serve as a baseline for developmental studies of the oral cavity using this teleost as a model.

The ultrastructural modifications that occur on the ependymal surface of the lateral ventricles of prenatal rabbit brains at 25, 27, 29 days of pregnancy, of term fetuses (30-31 days) and of 5, 10, 15 day old newborn rabbits, were studied by a SEM. On the ependymal surface the cilia, usually associated in tufts and the microvilli, variable in size and number, that surround them, show a rate of development correlated to the age. The results show the early differentiation of the surface features commensurated with early cerebrospinal fluid (CSF) functioning.