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The current investigation focuses on gross anatomy, light, and scanning electron microscopy (SEM) of the Testudo graeca oropharyngeal floor, with particular reference to the immunofluorescence technique to examine its tongue. The T. graeca oropharyngeal floor showed many anatomical structures: the lower rhamphotheca, paralingual ridge, lower alveolar ridge, tongue, laryngeal mound, and glottis. The lower rhamphotheca appeared as a V-shaped jaw line with a highly serrated edge and a median tomium (beak). SEM observations of the lingual apex and the lingual body showed rectangular and conical filiform papillae with porous surfaces and taste pores. Meanwhile, the lingual root had two wings that carried papillae with different shapes: dagger-shaped, conical, bifurcated, and leaf-like papillae, and these papillae lacked taste pores. The laryngeal mound had openings for the laryngeal mucus gland and its secretions. Light microscopy findings showed mucous glands in the propria submucosa and near the mucosal surface of the lingual apex. The lingual root had lingual papillae and two hyaline cartilaginous skeletons between skeletal muscles, and the lingual papillae were elongated filiform, rectangular filiform papillae, and fungiform papillae. The lamina propria constituted the core of the lingual papillae and the mucous gland, they had a positive reaction with the periodic acid schiff (PAS) reagent. The apical surface of the fungiform papillae had taste pores. Under immunofluorescence, the vimentin was detected in taste bud cells, and synaptophysin reacted to the taste buds and nerve bundles. The current study of the Greek tortoise oropharyngeal floor investigated its herbivorous eating habits using its serrated lower rhamphotheca, a large tongue with differently shaped papillae, and numerous mucous glands. RESEARCH HIGHLIGHTS: The Greek tortoise (T. graeca graeca) oropharyngeal floor showed many anatomical structures: lower rhamphotheca, paralingual ridge, lower alveolar ridge, tongue, laryngeal mound, and glottis. SEM and light microscopy observations of the tongue revealed varied types and shapes of lingual papillae with a porous surface on the tongue apex (rectangular or conical filiform papillae), on the tongue body (filiform and fungiform papillae), and on the tongue root (dagger-shaped, conical, bifurcated, and leaf-like papillae). Light microscopy findings: the lamina propria constituted the core of the lingual papillae and had numerous mucous glands that had a slightly magenta-red color with PAS reagent. The apical surface of the fungiform papillae had taste pores. Vimentin and synaptophysin gave a reaction to the taste buds., (© 2024 Wiley Periodicals LLC.)

Background: Eonycteris spelaea ( E. spelaea ) is a sizable nectar-feeding bat that falls within the taxonomic classification of order Chiroptera and family Pteropododae. The form and structure of the tongue play a crucial role for bats in the intake and digestion of food in their mouth. Each papilla's morphology, dimensions, spatial arrangement, and physiological role exhibit variations among different animal species, contingent upon their respective lifestyles., Aim: This research attempts to examine the morphology and microstructure of the E. spelaea tongue papillae, collected from Timor Island, East Nusa Tenggara, Indonesia., Methods: This study aimed to achieve a scanning electron microscope and a light microscope in the presence of hematoxylin-eosin staining and employed a sample of 6 sexually indiscriminate adult E. spelaea bats., Results: The tongue of E. spelaea is separated into three distinct parts: the apex, corpus, and radix. The structure's apex contains filiform papillae, which come in many varieties, such as scale-like filiform papilla, enormous trifid papilla, and little crown-like papilla. Additionally, there is a cluster of fungiform papillae on the outside edge of the highest point and transitional papillae connecting the large trifid papillae with the smaller crown-like papillae. The corpus section comprises two papilla types: filiform papilla (leaf-shaped filiform papilla and big crown-like papilla) and fungiform papilla. The radix comprises the elongated conical papilla, rosette-shaped filiform papilla, short conical papilla, transitional papilla, and three circumvallate papillae at the back of the tongue., Conclusion: The tongue papillae of E. spelaea comprise a wide variety of mechanic papillae and also sensory papillae which have specific dietary regimens in their living habitat., Competing Interests: The authors declare that there is no conflict of interest.

The aim of this study was to describe the morphology of the tongue of the okapi, and to compare the results with other ruminants including browsers, intermediates and grazers. The material was collected post-mortem from two animals from a Zoological Garden. The structure of the okapi tongue, focusing of the shape of the tongue, lingual surface, its papillae and lingual glands, was examined using gross morphology, light and polarized microscopy, and by scanning electron microscopy. The okapi tongue was characterized by dark pigmentation on the lingual dorsum (except lingual torus) and on the whole ventral surface. Two types of filiform papillae were observed, with additional, even 6-8 projections at their base. The round fungiform papillae were present at a higher density, up to 16/cm 2 , on the ventro-lateral area of the lingual apex. Round and elongate vallate papillae were arranged in two parallel lines between the body and root of the tongue. Numerous taste buds were detected within the epithelium of their vallum, while fungiform papillae had sparse taste buds. A lack of foliate papillae was noted. Very small conical papillae, some lenticular in shape, were present on the lingual torus. Thick collagen type I fibers were dominant over collagen type III fibers in the connective tissue of the lingual papillae. The mucous acini units were dominant among lingual glands, indicating that the secretion of okapi lingual glands was mostly mucous. In many aspects, the tongue of okapi resembles the tongue of other ruminants. The specific lingual shape and lingual surface, together with the lingual glands, support the processing of plant food, such as young and soft leaves. Although okapi tongue is characterized by smaller conical papillae compared to other ruminants, its high number of vallate papillae is similar that found in other browsers, intermediate and grazers. Thus the number of gustatory papillae rather indicates that this feature is not related to the type of feeding., (© 2024 Wiley Periodicals LLC.)

Morphological study of the tongue is an interesting way of understanding evolutionary processes associated with feeding habits. Therefore, the aim of the present study was to describe the tongue morphology of the Antillean manatee and to understand possible morphological relationships with its way of capturing food. Macroscopic dissections and light and scanning electron microscopy analyses of seven manatee tongues were performed. The tongue in Antillean manatees is a muscular and robust organ, divided into apex, body, and root. It is firmly adhered to the floor of the oral cavity. Lingual papillae were distributed over the entire tongue surface. They were identified as filiform papillae concentrated in the apex. Fungiform papillae were present on the apex and lateral regions. Foliate papillae were located on the dorsolateral portion of the root. Lentiform papillae were located across the dorsal tongue surface. The mucosa was lined by a keratinized stratified squamous epithelium presenting compound tubuloacinar glands and taste buds in the foliate papillae. The tongue of the Antillean manatee is similar to other Sirenia species, both of which share a completely herbivorous diet., Competing Interests: Conflict of Interest The authors declare that they have no conflict of interest., (© Crown copyright 2023.)

The evolution of the tongue in tetrapods is associated with feeding in the terrestrial environment. This study analyzes the tongue morphology of two closely related frog species, Telmatobius oxycephalus and T. rubigo, which exhibit contrasting feeding mechanisms. Telmatobius oxycephalus, a semi-aquatic species, relies on its tongue to capture terrestrial prey whereas T. rubigo, a secondarily aquatic species, uses suction feeding not involving the tongue. Through anatomical, histological and scanning electron microscopy analyses, we revealed remarkable differences in tongue morphology between these species. Telmatobius oxycephalus exhibits a well-developed tongue whose dorsal epithelium has numerous and slender filiform papillae. The epithelial cells of the papillae are protruded and have a complex array of microridges. In contrast, T. rubigo possesses a reduced tongue with flat and less numerous filiform papillae. The epithelial cells are completely flat and lack microridges. These findings highlight the remarkable adaptability of lingual morphology in Telmatobius to respond to the contrasting ecological niches and prey capture mechanisms. This study sheds light on the relationship between tongue shape and the different functional demands, contributing to our understanding of the evolution of prey capture mechanisms in amphibians., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Trichiurus lepturus is a carnivorous fish, and most of the previous anatomical research has focused on computed tomography imaging and histology of their teeth and fangs, while the remaining structures of pharyngeal cavity remain unexplored. The present research is the first to use anatomical examinations alongside scanning electron microscopy to investigate the T. lepturus oral cavity. The oropharyngeal roof included teeth, upper lip, rostral and caudal velum and the palate. The middle of the palate showed a median groove flanked by two folds, followed by a median band flanked by micro-folds, thereafter the palate became crescent shaped. The lateral regions of the palate exhibited longitudinal folds that extended rostrally towards the fangs. The oropharyngeal floor had two cavities which acted as a scabbard for the premaxillary fangs and upper velum, while the caudal sublingual cavity contained two oyster-shaped structures on the outer surface plus sublingual ridges and sublingual clefts. The tongue apex exhibited a spoon-like shape, its body demonstrated a median elevation and the root with two lateral branches contained only dome-shaped papillae. Taste buds were located on the upper velum, lower lip and the caudal part of the interbranchial septum. Images and descriptions of T. lepturus tooth structure are also provided. The present research, using anatomical dissection and morphological observation using scanning electron microscopy, has identified the structures of the dentition system, a variety in shapes of the folds and microridges, and identified the taste buds and mucous pores in the T. lepturus oropharyngeal cavity., (© 2023 The Authors. Anatomia, Histologia, Embryologia published by Wiley-VCH GmbH.)

Background: We sought to determine whether ongoing taste disturbance in the postacute sequelae of coronavirus disease 2019 period is associated with persistent virus in primary taste tissue., Methods: We performed fungiform papillae biopsies on 16 patients who reported taste disturbance lasting more than 6 weeks after molecularly determined severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Then, on multiple occasions, we rebiopsied 10 of those patients who still had taste complaints for at least 6 months postinfection. Fungiform papillae obtained from other patients before March 2020 served as negative controls. We performed hematoxylin and eosin staining to examine fungiform papillae morphology and immunofluorescence and fluorescence in situ hybridization to look for evidence of persistent viral infection and immune response., Results: In all patients, we found evidence of SARS-CoV-2, accompanying immune response and misshapen or absent taste buds with loss of intergemmal neurite fibers. Six patients reported normal taste perception by 6 months postinfection and were not further biopsied. In the remaining 10, the virus was eliminated in a seemingly random fashion from their fungiform papillae, but four patients still, by history, reported incomplete return to preinfection taste perception by the time we wrote this report., Conclusions: Our data show a temporal association in patients between functional taste, taste papillae morphology, and the presence of SARS-CoV-2 and its associated immunological changes. (Funded by Intramural Research Program/National Institute on Aging/National Institute of Allergy and Infectious Diseases/National Institutes of Health; ClinicalTrials.gov numbers NCT03366168 and NCT04565067.).

Morphological studies on the oropharyngeal cavity of turtles are an interesting tool in understanding evolutionary processes associated with feeding habits. There is paucity of morphological information on the oropharyngeal cavity of the Trachemys adiutrix turtle. Thus, the aim of this study was to describe the tongue and palate morphology of T. adiutrix to establish a standard model for the species, providing information that may improve knowledge on the species feeding habits. Gross dissection, light microscopy and scanning electron microscopy assessments of 11 specimens were carried out. The tongue of T. adiutrix is triangular with a slightly rounded apex and broad base and lingual papillae widely distributed throughout the entire dorsal surface. The palate is composed of bony structures, displaying a triangular apex with one pair of choanae and palatine raphe that begin in the middle region, dividing the two openings. The body was elongated and smooth. The root was wrinkled and opened into the oesophagus. The tongue was lined by non-keratinized stratified squamous epithelium, rich in mucous cells and a large number of different-shaped papillae and taste buds. The palate was mainly lined by a pseudostratified cylindrical ciliated epithelium rich in mucous cells. In conclusion, the tongue and palate characteristics of T. adiutrix include evidence that these animals are semiaquatic, displaying morphological characteristics associated with aquatic and terrestrial trophic ecology, similar to that observed in other semiaquatic and terrestrial chelonian species., (© 2023 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.)

The rat is one of the most commonly used animals in biological research and experimental investigations in medicine. The ultrafine structural components of the epithelium differ depending on the anatomy of the animal and the papilla type. Animal adaptation to food types and environmental circumstances may also be linked to morphological diversity. In the current study, seven male Wistar rat tongues were investigated. For scanning electron microscope (SEM), two rat tongues were immersed in a 10% formalin solution and the other two rat tongues were immersed in a 2.5% glutaraldehyde solution. The tongues of three rats were fixed for regular histological evaluation using triple staining. The three primary components of the Wistar rat tongue are the apex, body and root. The apex had a rounded and bifurcated shape. Filiform papillae and gustatory papillae were easily identified on the dorsal side of the tongue. There were three forms of gustatory papillae; fungiform papillae, vallate papillae and foliate papillae. The purpose of this study was to expose the tongue morphology of the Wistar rat species, which is widely used in investigations. Also, we wanted to show that formalin fixation can be utilized for morphological research in SEM. Finally, the Wistar rat tongue was thoroughly investigated and compared to those of other species., (© 2022 Wiley Periodicals LLC.)

There are variations in the tongue papillae among species, including the size, number and type of papillae. There have been no studies describing the detailed tongue morphology of Javan mongoose (Herpestes javanicus). Therefore, we analysed the tongue and lingual structures of Javan mongoose (H. javanicus), using scanning electron microscopy and light microscopy. The tongue was covered by papillae and rough in appearance. We divided the tongue into three regions: the apex, corpus and radix of the tongue. The medioventral section of the tongue was characterized by the presence of a frenulum. We identified four types of papillae: filiform, fungiform, conical and vallate papillae. There were two subtypes of filiform papillae: leaf-like and conical. Both were seen on the apex, although leaf-like filiform papillae also extended to the corpus. Fungiform papillae had taste buds on their dorsal surfaces and were observed from the apex to the radix. Vallate papillae, three in numbers only occurred on the radix. Periodic acid-Schiff (PAS) staining showed minor lingual glands on the textus muscularis striatus syncytialis of the corpus and lateral radix, which we identified as Weber glands; we also observed von Ebner glands on this layer of the tongue. These anatomical features of the Javan mongoose tongue are broadly similar to those seen in other carnivores, with some specific differences, such as the number of vallate papillae., (© 2022 Wiley-VCH GmbH.)

Several studies have used taste sensitivity to 6-n-propylthiouracil (PROP) to evaluate interindividual taste variability and its impact on food preferences, nutrition, and health. We used a supervised learning (SL) approach for the automatic identification of the PROP taster categories (super taster (ST); medium taster (MT); and non-taster (NT)) of 84 subjects (aged 18-40 years). Biological features determined from subjects were included for the training system. Results showed that SL enables the automatic identification of objective PROP taster status, with high precision (97%). The biological features were classified in order of importance in facilitating learning and as prediction factors. The ratings of perceived taste intensity for PROP paper disks (50 mM) and PROP solution (3.2 mM), along with fungiform papilla density, were the most important features, and high estimated values pushed toward ST prediction, while low values leaned toward NT prediction. Furthermore, TAS2R38 genotypes were significant features (AVI/AVI, PAV/PAV, and PAV/AVI to classify NTs, STs, and MTs, respectively). These results, in showing that the SL approach enables an automatic, immediate, scalable, and high-precision classification of PROP taster status, suggest that it may represent an objective and reliable tool in taste physiology studies, with applications ranging from basic science and medicine to food sciences.

Tongue fungiform papillae contain taste buds crucial for taste and hormone-producing taste receptor cells; therefore, they may be considered as endocrine organs and have important age-associated physiological implications. We examine the cross-sectional and longitudinal trajectories of fungiform papillae density in 1084 participants from the Baltimore Longitudinal Study of Aging using linear regression models and mixed effects models. At baseline, the mean age was 67.86 ± 14.20 years, with a mean follow-up time among those with repeat visits of 4.24 ± 1.70 years. Women (53%) were younger (66.85 ± 13.78 vs. 69.04 ± 14.61 years, p < 0.001) and had a higher fungiform papillae density than men (16.14 ± 9.54 vs. 13.77 ± 8.61 papillae/cm 2 , p < 0.001). Whites (67%) had a lower fungiform papillae density than non-Whites after adjusting for age and sex. Factors cross-sectionally associated with a lower fungiform papillae density included a higher waist-hip ratio (β = -8.525, p = 0.029), current smoking status (β = -5.133, p = 0.014), and alcohol use within the past 12 months (β = -1.571, p = 0.025). Longitudinally, fungiform papillae density decreased linearly with follow-up time (β = -0.646, p < 0.001). The rate of decline was not affected by sex, race, BMI, waist-hip ratio, smoking, or alcohol use. The longitudinal decline of fungiform papillae density over time needs to be explored further in order to identify other possible age-associated physiological determinants.

Current understanding of functional characteristics and biochemical pathways in taste bud cells have been hindered due the lack of long-term cultured cells. To address this, we developed a holistic approach to fully characterise long term cultured bovine taste bud cells (BTBCs). Initially, cultured BTBCs were characterised using RT-PCR gene expression profiling, immunocytochemistry, flowcytometry and calcium imaging, that confirmed the cells were mature TBCs that express taste receptor genes, taste specific protein markers and capable of responding to taste stimuli, i.e., denatonium (2 mM) and quinine (462.30 μM). Gene expression analysis of forty-two genes implicated in taste transduction pathway (map04742) using custom-made RT-qPCR array revealed high and low expressed genes in BTBCs. Preliminary datamining and bioinformatics demonstrated that the bovine α-gustducin, gustatory G-protein, have higher sequence similarity to the human orthologue compared to rodents. Therefore, results from this work will replace animal experimentation and provide surrogate cell-based throughput system to study human taste transduction.

Many herbivorous insects are mono- or oligophagous, having evolved to select a limited range of host plants. They specifically identify host-plant leaves using their keen sense of taste. Plant secondary metabolites and sugars are thought to be key chemical cues that enable insects to identify host plants and evaluate their quality as food. However, the neuronal and behavioral mechanisms of host-plant recognition are poorly understood. Here, we report a two-factor host acceptance system in larvae of the silkworm Bombyx mori, a specialist on several mulberry species. The first step is controlled by a chemosensory organ, the maxillary palp (MP). During palpation at the leaf edge, the MP detects trace amounts of leaf-surface compounds, which enables host-plant recognition without biting. Chemosensory neurons in the MP are tuned with ultrahigh sensitivity (thresholds of attomolar to femtomolar) to chlorogenic acid (CGA), quercetin glycosides, and β-sitosterol (βsito). Only if these 3 compounds are detected does the larva make a test bite, which is evaluated in the second step. Low-sensitivity neurons in another chemosensory organ, the maxillary galea (MG), mainly detect sucrose in the leaf sap exuded by test biting, allowing larvae to accept the leaf and proceed to persistent biting (feeding). The two-factor host acceptance system reported here may commonly underlie stereotyped feeding behavior in many phytophagous insects and determine their feeding habits., Competing Interests: The authors have declared that no competing interests exist.

This study aimed to investigate the postnatal morphological features of rabbit's lingual gustatory papillae using histological, histochemical, morphometrical and scanning electron microscopical studies. A total of 48 New Zealand rabbits (1, 7, 15, 23, 30, 60 days postnatal) were used as the material. Tongue consisted of an apex, body and root with three types of gustatory papillae fungiform, vallate and foliate. Rounded to oval fungiform papillae were distributed on lingual apex among filiform papillae. Two foliate papillae on lateroposterior side have parallel folia increased progressively in number (14-20) with age advancement. Two oval vallate papillae on lingual root surrounded by annular grooves. Histologically, the gustatory papillary epithelium was thin at birth then increased in stratification and cornification from third to fourth week. Vallate and foliate grooves were shallow in newborns then grew deeply by desquamation of their lining epithelium which completely opened and connected with lingual excretory ducts at 23 days. Developing serous von Ebner's glands appeared at 23 days and became lobulated form 1-2 months. They gave a negative reaction with Periodic Acid Schiff-Alcian blue stain, while mucous Weber's glands showed Alcian blue positive reaction. Taste buds were firstly seen at 15 days old, increased in number and size and became mature with taste pores from third to fourth week. They distributed dorsally on fungiform and on lateral sides of vallate and foliate. This structural adaptation and maturity of gustatory papillae to meet the functional demands of food ingestion during the transition from suckling to dry matter feeding.

This study was carried on the tongues of ten normal, healthy and adult fruit bats (Rousettus amplexicaudatus, also known as the nyap biasa bat) in Yogyakarta, Java Island, Indonesia. The tongue was protrusible, elongated and flat with a rounded apex, and its width and thickness increased gradually towards to lingual root. There were two main types of lingual papillae, mechanical (filiform) and gustatory (fungiform and circumvallate). The tongue was divided into three parts (apex, corpus and radix), and then, each part was subdivided into three regions (two lateral regions and a median region). There were six subtypes of the filiform papillae-three types on the anterior part (small, scale-like and giant), one type on the middle part (leaf-like papillae) and two types on the posterior part (rosette-shaped filiform and conical filiform papillae)-in addition to transitional papillae presented on the corpus and radix. Two types of gustatory papillae were represented by a small number of fungiform papillae that are scattered among the filiform papillae on the lingual apex and corpus, while three circumvallate papillae on the posterior part are arranged in a "V" shape pointing directly at the larynx., (© 2019 Blackwell Verlag GmbH.)

Objectives/hypothesis: The larynx is a highly responsive organ exposed to mechanical, thermal, and chemical stimuli. Chemicals elicit responses both in intraepithelial nerve fibers and in specialized chemosensory cells, including scattered solitary cells as well as taste cells organized into taste buds. Activation of both chemosensory cells and taste buds in the larynx elicit cough, swallow, or apnea with exposure to sour or bitter substances, and even by water or sweet-tasting chemicals. In an effort to begin understanding their function, we sought to compare the distribution, density, and types of chemosensory cells and chemoresponsive nerve fibers in laryngeal epithelium of humans and mice., Study Design: Animal and human laboratory analysis., Methods: Using immunohistochemistry, we identified taste cells and polymodal nociceptive nerve fibers in the arytenoid area of the laryngeal epithelium of the following: 1) infants undergoing supraglottoplasty for laryngomalacia, and 2) a cadaveric specimen procured from a 34-year-old donor. We then compared these findings to both preweanling and mature mouse tissue., Results: Arytenoid tissue from both human and mouse contained many taste buds containing type II taste cells-bitter, sweet, or umami sensing-which were innervated by nerve fibers expressing P2X3 type adenosine triphosphate receptors. Type III cells (acid responsive) were also present, but they were fewer in human tissue than in equivalent tissue from mice. In both species, the epithelium was densely innervated by free nerve endings., Conclusions: Our findings suggest that from a standpoint of chemosensation, human and mouse larynges are biologically similar. This suggests that a murine model can be used effectively in laryngeal chemosensory research., Level of Evidence: NA Laryngoscope, 130:423-430, 2020., (© 2019 The American Laryngological, Rhinological and Otological Society, Inc.)

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.)

The African giant pouched rat is a nocturnal, fossorial and omnivorous wild rodent widely distributed in sub-Saharan Africa. The morphology of lingual surface has not previously examined and was investigated by gross dissection, stereomicroscopy, scanning electron and light microscopy. Grossly, it was elongated and dorso-ventrally flattened with rounded tip. It measured 3.48 ± 0.33 cm in length, with a median groove of 1.4 ± 0.1 cm in length and well-developed lingual prominence. Stereomicroscopically, filiform, fungiform and vallate papillae were indicated in the apex, body and root. Fungiform papillae intermingled with filiform on the ventral and dorsal surface of the apex and body. Three vallate papillae were located in triangular arrangement on the root. The surface ultrastructural features distinguished four types of filiform which varied in size, shape and distribution: first type with long pointed process was preponderant on the apex and body of tongue; the second with robust base was located on central lingual prominence; the third (caudal body) was conically shaped with pointed process; and the fourth type (root) had forked filamentous process. Large oval-shaped fungiform papillae were apparent. Each vallate was surrounded by a circumferential groove into which taste pores opened. Histologically, the tongue surface displayed moderately keratinized stratified squamous epithelium, and lamina propria that varied in places. Fungiform and vallate showed spindle-shaped taste buds. Serous and mucous acini containing neutral and acidic mucins were observed in lamina propria of root. The structural adaptations of the tongue to omnivorous diet and food manipulation in oral cavity were comparatively discussed., (© 2019 Blackwell Verlag GmbH.)

The ocelot (Leopardus pardalis) is a Felidae of wide geographical distribution and food flexibility; therefore, it is essential to understand the morphology of the species. Thus, we aimed to describe its lingual morphology in order to gain information regarding the anatomy of this carnivore's digestive system. The tongues ​​were removed for ex situ macroscopic and morphometric analyses, as well as for light microscopy and scanning electron microscopy, of fragments of the different lingual regions. The tongue of L. pardalis had an elongated form that was subdivided into the apex, body and root, in which four papillary types were observed: filiform, fungiform, circumvallate and conical. It presented with a stratified, keratinized squamous epithelium, followed by loose and dense connective tissues, as well as a skeletal striated musculature that comprised most of the organ. In addition, in scanning electron microscopy the filiform papillae showed a complex with multiple layers of keratin with triangular shape projected caudally in oral cavity. The fungiform papillae were distributed among the filiform and showed a rounded shape with some gustatory pores, and are keratinized but in a lower intensity if compared with filiform. The vallate papillae, located in lingual root, showed an oval format, had a deep groove surrounded the papillae and some gustatory pores. The conical papillae are located in lingual root and are similar to the filiform. The tongue of L. pardalis resembles other carnivorous species, mainly among felids. However, it differed in relation to the quantity of vallate papillae and the absence of foliate papillae., (© 2019 Blackwell Verlag GmbH.)

Feral cats are considered as strays and are more likely to hunt in the street. We investigated the effect of environmental adaptations on the structures of lingual papillae in feral cats, which could be used as forensic evidence for their identification. There are no reported studies about the structural comparison of lingual papillae between suckling and adult feral cats. The present study described the lingual papillae of both suckling and adult cats macroscopically and microscopically via light and scanning electron microscopy. A total of nine tongue samples each for suckling and adult feral cats were examined grossly and histologically. Papillae distributions of suckling cats were similar to those observed in adult cats. Meanwhile, the shapes of those papillae were markedly different from that of corresponding papillae in adults. The change in taste bud position and size seemed to be related to the progressive growth of the papillae between adult and suckling cats; absence of taste buds in foliate papillae of feral cats at any stage; and marginal papillae which were a characteristic feature for all suckling cats. All previous elements could be affected by the specific feeding behaviour and mastication mode adaptation in suckling and adult feral cats which might help to identify suckling and adult feral cats among other breeds and animal species. We anticipate these findings may provide promising forensic evidence to discriminate between adult and suckling feral cat remains as well as prediction of environmental harshness and feeding behaviour., (© 2019 Blackwell Verlag GmbH.)

While epiglottis is essentially a mammalian structure, studying its microstructure in any placental model will add an important information to the field of comparative anatomy and the related branches of biology. The aim of this study was to describe the structure of the epiglottis in dromedary camels using light and scanning electron microscopy (SEM), with reference to the possible functions. A total of 11 epiglottis cartilages from 11 larynges were used. The study revealed unusual, deeply situated glands just beneath the cartilage plate. They have unusually, wide surface-openings, while their ducts were partly located within the cartilage. This is presumed to be an adaptation to the need for rapid and efficient mucosal surface hydration in the arid conditions. The possible secretion transport mechanisms in these glands were also discussed. Furthermore, the SEM revealed for the first time, the presence of taste buds in camel epiglottis. However, in histological sections, visibility of taste buds was dependent upon the staining techniques. The taste buds were not seen with standard H& E stain, as they blended imperceptibly with the surrounding epithelium. Conversely, Mallory's trichrome showed contrasting colors, and taste buds were visible. In conclusion, camel epiglottis has an unusual structure, which may be correlated to environmental adaptation and important for the general health of upper respiratory tract in this species., (© 2019 Wiley Periodicals, Inc.)

Fungiform papillae are raised lingual structures which contain taste buds and thus play an important role in taste perception. These structures vary in number due to their relative sensitivity to a range of systemic and local factors which affect the dorsum of the tongue. Taste sensation can be measured using both chemical and electrical methods; however, the number of fungiform papillae has a direct effect on chemogustometric and electrogustometric values during evaluation. This review provides a general overview of fungiform papillae , their quantification methods and the various factors which may affect these structures. In addition, numerous methods of recording taste sensation and their clinical applications are highlighted., (© Copyright 2019, Sultan Qaboos University Medical Journal, All Rights Reserved.)

Fungiform papillae house taste buds on the anterior dorsal tongue. Literature is inconclusive as to whether taste perception correlates with fungiform papillae density (FPD). Gustatory reflexes modulate the amount and composition of saliva subsequently produced, and thus may be a more physiologically objective measure of tastant-receptor interactions. Taste perception fluctuates with time but the stability of individual fungiform papillae is unclear. This study followed ten healthy volunteers longitudinally at baseline, one and six months. FPD, diameter and position were measured and participants rated intensity perception of sucrose, caffeine, menthol and capsaicin solutions. Salivary flow rate, protein concentration and relative changes in protein composition were measured following each tastant. FPD, diameter and position were unchanged at six months. FPD did not correlate with intensity rating for any taste. FPD did correlate with changes in salivary protein output following sucrose (ρ = 0.72, p = 0.02) and changes in levels of proline-rich protein and mucin 7 following capsaicin (ρ = 0.71, p = 0.02, ρ = 0.68, p = 0.04, respectively). These results suggest that over six months fungiform papillae are anatomically stable, playing a greater role in mediating the physiological salivary response to stimuli rather than determining the perceived intensity of taste.

The adaptability of the taste system in fish has led to a large variety in taste bud morphology, abundance and distribution, as well as in taste physiology characteristics in closely related species with different modes of life and feeding ecology. However, the modifications evoked in the sense of taste, or gustation, particularly during ontogeny when fishes are subject to different environmental variables, remain poorly studied. This review paper focusses on current knowledge to show how plastic and resistant the taste system in fishes is to various external factors, linked to other sensory inputs and shifts in physiological state of individuals. Ambient water temperature is fundamental to many aspects of fish biology and taste preferences are stable to many substances, however, the taste-cell turnover rate strongly depends on water temperature. Taste preferences are stable within water salinity, which gives rise to the possibility that the taste system in anadromous and catadromous fishes will only change minimally after their migration to a new environment. Food-taste selectivity is linked to fish diet and to individual feeding experience as well as the motivation to feed evoked by attractive (water extracts of food) and repellent (alarm pheromone) odours. In contrast, starvation leads to loss of aversion to many deterrent substances, which explains the consumption by starving fishes of new objects, previously refused or just occasionally consumed. Food hardness can significantly modify the final feeding decision to swallow or to reject a grasped and highly palatable food item. Heavy metals, detergents, aromatic hydrocarbons and other water contaminants have the strongest and quickest negative effects on structure and function of taste system in fish and depress taste perception and ability of fishes to respond adequately to taste stimuli after short exposures. Owing to phenotypic plasticity, the taste system can proliferate and partially restore the ability of fishes to respond to food odour after a complete loss of olfaction. In general, the taste system, especially its functionality, is regarded as stable over the life of a fish despite any alteration in their environment and such resistance is vital for maintaining physiological homeostasis., (© 2019 The Fisheries Society of the British Isles.)

An ontogenetic analysis of the olfactory organ and the number and distribution of internal taste buds was carried out in two neon gobies (Elacatinus lori and Elacatinus colini) with the goal of revealing morphological trends that might inform an understanding of the roles of olfaction and taste in larval orientation behaviour. The pattern of development of the olfactory organ is unremarkable and enclosure of the olfactory epithelium occurs concurrently with metamorphosis and settlement in both species. Like other gobies, juvenile and adult E. lori and E. colini lack complex olfactory lamellae, and lack the accessory nasal sacs present in some adult gobies that could facilitate active olfactory ventilation (i.e., sniffing). A small number of internal taste buds are present at hatch with most found in the caudal region of the buccal cavity (on gill arches, roof of buccal cavity). As taste bud number increases, they demonstrate an anterior spread to the lips, buccal valves and tongue (i.e., tissue covering the basihyal). In the absence of an active ventilatory mechanism for the olfactory organs, the water that moves through the buccal cavity with cyclic gill ventilation may provide chemical cues allowing the internal taste buds to play a role in chemical-mediated orientation and reef-seeking behavior in pelagic larval fishes., (© 2018 The Fisheries Society of the British Isles.)

The sense of taste relies on well-defined neuroanatomical structures, namely, the taste buds and afferent nerve fibers. Taste buds are clusters of 50-100 neuroepithelial cells located throughout the oral cavity, including the epiglottis and larynx. They are responsible for the initial transduction process that ultimately results in the perception of bitter, sour, salty, sweet, and umami (savory) sensations. They service as the initial sentinel for a sensory system critical in evolution for distinguishing "dangerous" food components, often perceived as bitter or unpleasant, from "useful" ones, often perceived as pleasant, salty, or sweet. This chapter describes the anatomy and development of the human peripheral taste system and provides historical context for what is presently known about this element of this important sensory system. Its main focus is on the fundamental question of how tastants are perceived-a question that has been of philosophical and scientific interest for more than two millennia. Descriptions of lingual and extralingual taste buds, their blood and nerve supplies, and the associated salivary glands are provided, including details of their microstructure and transduction mechanisms., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Bagrus Bayad (Forskal, 1775) is a bottom feeder fish feeds on different food items. Its oral cavity anatomy has many types of teeth adapted to the capacity and varieties of feeding. The aim of the present study was to use the gross anatomy and scanning electron microscopy to identify the anatomical characteristic, especially of the teeth and taste buds distributed on the roof and floor of the oropharyngeal cavity. The results clarified that Bagrus Bayad has two types of teeth; curved pointed and blunt teeth of different sizes. The teeth appeared on epithelial protrusions. The pharyngeal region had upper and lower pharyngeal teeth, the upper arranged into two oval prominences while the lower ones arranged into two triangular areas. The higher number of the pointed teeth is prove the carnivorous nature of the Bagrus Bayad. Three types of taste bud (I, II, & III) were found in the oropharyngeal cavity. The tongue present in the floor and free from teeth and characterized by the presence of taste bud type I and II. Many microridges of different arrangement observed on the surface epithelium of oropharyngeal cavity. The upper and lower valve characterized by the microridges, pores and taste buds. The knowledge of the nature of the oropharyngeal cavity of the Bagrus Bayad helps in identifying new and better methods for feeding in aquaculture., (© 2018 Wiley Periodicals, Inc.)

The large bamboo rat (Rhizomys sumatrensis) is a fossorial rodent found throughout Indochina that has a distinct habitat dominated by bamboo thickets. In the study reported here, the lingual biology of this rodent is described in detail, based on characteristic features of the tongue and lingual papillae as determined by light and scanning electron microscopy studies. The tongue was found to be elongated with a rounded apex and possessed a median groove and a well-developed intermolar prominence. Three types of the papillae were found on the dorsal lingual surface: filiform, fungiform and vallate papillae. The most abundant papillae were the filiform papillae, the majority of which had a wide base and fork-like processes. Rounded fungiform papillae with one to four taste buds were randomly distributed among the filiform papillae, with a high density found at the anterior tongue, particularly the apex. Two oval vallate papillae were observed on the posterior part of the tongue, surrounded by a circumferential groove into which their numerous gustatory pores opened. The lingual radix had no papillae but contained mucus-secreting Weber's salivary glands. Structural adaptations of the tongue to meet the functional demands of food ingestion and food manipulation in the oral cavity are also discussed.

This study presents the histomorphological features of tongue in Eurasian teal (Anas crecca); the smallest extant dabbling duck. Heads of four adult males and four adult females were used in this study. The results illustrate a tongue with three different parts; the apex with a lingual nail in ventral surface, the body with a lingual prominence in caudal part and some large and small conical papillae in lateral sides and the root, that was covered with many conical papillae in different sizes. Histological results revealed two types of keratinized and non-keratinized epithelium covering parts of the tongue. The lingual salivary glands were observed in the lamina propria of the body and root of the tongue showed strongly periodic acid-Schiff (PAS)-positive reaction. The yellow adipose tissue was located under the lamina propria on the body and root of the tongue. The filiform papillae between the conical papillae of the body were arranged densely. The sensory organs, which contain sensory receptors (Grandry and Herbst corpuscles), were located in the lamina propria of the body of the tongue. In conclusion, the anatomical and histological structure of the Eurasian teal' tongue was generally similar to its family members such as domestic goose and duck but showed some differences that may be adoptions to the bird's habitat and mode of feeding., (© 2017 Blackwell Verlag GmbH.)

Despite its contribution to food perception, lingual tactile sensitivity has been understudied. We hypothesized that sensitivity to threshold and suprathreshold tactile stimuli varies in the population and sought to determine proximate sources of variability. Forty-eight adults were tested for lingual threshold sensitivity via a modified letter identification task and suprathreshold sensitivity via estimation of stimulus size using magnitude estimation. In addition, taste bud density on the anterior tip of each panelist's tongue was estimated by counting the number of fungiform papillae in a 0.317 cm 2 circumscribed area. Lingual tactile thresholds were significantly impacted by age group as subjects 40 years or older had higher thresholds than those in their 20s. Moreover, threshold sensitivity increased with increasing fungiform papillae count. Suprathreshold estimates of size were not affected by age group, sex, or fungiform papillae count.

The objective of this study was to evaluate differences in gustatory function and in shape, density, and vascularization of the fungiform papillae (fPap) of smokers' tongue before and after smoking cessation. In 24 smokers (19 males, 5 females; median age: 54.6 ± 2.9 years) electrogustometry (EGM) thresholds at the chorda tympani area, at the soft palate area and at the area of the vallate papillae were recorded bilaterally. Morphology and density of the fungiform papillae (fPap) and blood vessels' density and morphology at the tip of the tongue were examined using contact endoscopy (CE). Follow-up exams (EGM and CE) were performed on average 3.2 months after smoking cessation. Findings were compared between the 2 conditions as well as to those of a group of 24 non-smokers (median age: 55.2 ± 3.4 years; 19 males, 5 females). After smoking cessation, EGM thresholds decreased significantly (P = 0.02 or P = 0.03 depending on the tested area) but nonetheless still were quite different from those of non-smokers (P = 0.05 or 0.04 depending on the site of EGM measurement). Under CE the fPap density was higher after quitting smoking (P = 0.05) and the shape and vascularization of fPap also exhibited a trend to improvement (P = 0.05) after smoking cessation. Chronic exposure to cigarette smoke infers long lasting, although to a large extent reversible, alterations in morphology of taste buds in fungiform papillae, but rather irreversible EGM-related functional gustatory compromise, suggesting a profound physiologic effect on human peripheral taste organs., (© The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

This study described the morphological features of the Persian leopard (Panthera pardus saxicolor) tongue using light and scanning electron microscopy techniques. The keratinized filiform papillae were distributed all over the entire dorsal surface of the tongue and contained small processes. They were changed into a cylindrical shape in the body and conical shape in the root. The fungiform papillae were found on the apex and margin of the tongue. Few taste pores were observed on the dorsal surface of each papilla. The foliate papillae on the margins of the tongue were composed of several laminae and epithelial fissures. Taste buds were not seen within the non-keratinized epithelium. The vallate papillae were six in total and arranged in a "V" shape just rostral to the root. Each papilla was surrounded by a groove and pad. Taste buds were seen within their lateral walls. Lyssa was visible on the ventral surface of the tongue tip and was found as cartilaginous tissue surrounded by thin connective tissue fibres. The core of the tongue was composed of lingual glands, skeletal muscle and connective tissue. These glands were confined to the posterior portion of the tongue and were composed of many serous cells and a few mucous cells. The results of this study contributed to the knowledge of the morphological characteristics of the tongue of wild mammals and provided data for the comparison with other mammals., (© 2017 Blackwell Verlag GmbH.)

The oral cavity of vertebrates has a very important role in many functions strictly related to the food processing. Two species, sea bass Dicentrarchus labrax and seabream Sparus aurata, are mainly involved in the aquaculture industry in the mediterranean area; moreover, the white seabream Diplodus sargus sargus was recently chosen as the best candidate for the diversification of species of commercial interest. This investigation was carried out, using the standard procedures for light and scanning electron microscopy, to analyse the morphology of the tongue dorsal surface in order to show whether relationships are present between the tongue morphology and the nutritional choices of these species. In all the three investigated species, three different areas were observed on the dorsal lingual surface: an apex, a body and a root. In the sea bass D. labrax, numerous caninelike teeth, organized in pads, were present along the dorsal surface. The presence of numerous taste buds, scattered on the tongue, was shown. In the seabream S. aurata, the apical part of the tongue is inserted in a pouch with a characteristic medial ridge on the body surface. Numerous taste buds were scattered on the whole surface. In the white seabream D. sargus sargus, a pouch partially covering the apex was clearly observed. In the pouch, filiform-like and foliate-like papillae can be distinguished. The results show the important role of the fish tongue in the food ingestion process, demonstrating the interaction of food processing, taste and morphological characteristics., (© 2016 Blackwell Verlag GmbH.)

Objectives: The aim of this study was to characterize the histomorphometric features of subgemmal neurogenous plaques (SNPs) to better understand their relationship to surrounding microanatomy included in the tissue biopsy samples of the tongue., Study Design: A 12-year retrospective study on the files of 3 oral pathology centers yielded 28 SNPs. Hematoxylin and eosin-stained sections were used for histologic analysis, and immunohistochemical staining for S100 protein was performed to better characterize the neural structures. Slides were scanned and histomorphometric analysis carried out using ImageScope software., Results: Twenty-one women (75%) and 6 men (21.4%) comprised the sample (mean age 46.4 and 49 years, respectively). Twenty cases (71.4%) were juxtaposed to the tongue epithelium and 16 cases (57.1%) were associated with lymphoid tissue. The mean area of the SNPs was 0.160 mm 2 , and the mean distance to the overlying epithelium was 0.312 mm., Conclusions: SNPs are normal neural structures located on the posterior border of the tongue that represent a non-neoplastic regional anatomic variation. In some cases, signs or symptoms may be present, and further investigation should be performed. Pathologists should be aware of this entity to avoid confusion with neural lesions., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The aim of this study was to elucidate the relationship between the gustatory function and average number of taste buds per fungiform papilla (FP) in humans. Systemically healthy volunteers (n = 211), pre-operative patients with chronic otitis media (n = 79), and postoperative patients, with or without a chorda tympani nerve (CTN) severed during middle ear surgery (n = 63), were included. Confocal laser scanning microscopy was employed to observe fungiform taste buds because it allows many FP to be observed non-invasively in a short period of time. Taste buds in an average of 10 FP in the midlateral region of the tongue were counted. In total, 3,849 FP were observed in 353 subjects. The gustatory function was measured by electrogustometry (EGM). An inverse relationship was found between the gustatory function and average number of fungiform taste buds per papilla. The healthy volunteers showed a lower EGM threshold (better gustatory function) and had more taste buds than did the patients with otitis media, and the patients with otitis media showed a lower EGM threshold and had more taste buds than did postoperative patients, reflecting the severity of damage to the CTN. It was concluded that the confocal laser scanning microscope is a very useful tool for using to observe a large number of taste buds non-invasively., (© 2017 Eur J Oral Sci.)

Nerve fibers that surround and innervate the taste bud were visualized with inherent fluorescence using Brainbow transgenic mice that were generated by mating the founder line L with nestin-cre mice. Multicolor fluorescence revealed perigemmal fibers as branched within the non-taste epithelium and ending in clusters of multiple rounded swellings surrounding the taste pore. Brainbow-labeling also revealed the morphology and branching pattern of single intragemmal fibers. These taste bud fibers frequently innervated both the peripheral bud, where immature gemmal cells are located, and the central bud, where mature, differentiated cells are located. The fibers typically bore preterminal and terminal swellings, growth cones with filopodia, swellings, and rounded retraction bulbs. These results establish an anatomical substrate for taste nerve fibers to contact and remodel among receptor cells at all stages of their differentiation, an interpretation that was supported by staining with GAP-43, a marker for growing fibers and growth cones., (© 2016 Anatomical Society.)

In taste buds, glutamate plays a double role as a gustatory stimulus and neuromodulator. The detection of glutamate as a tastant involves several G protein-coupled receptors, including the heterodimer taste receptor type 1, member 1 and 3 as well as metabotropic glutamate receptors (mGluR1 and mGluR4). Both receptor types participate in the detection of glutamate as shown with knockout animals and selective antagonists. At the basal part of taste buds, ionotropic glutamate receptors [N-methyl-d-aspartate (NMDA) and non-NMDA] are expressed and participate in the modulation of the taste signal before its transmission to the brain. Evidence suggests that glutamate has an efferent function on taste cells and modulates the release of other neurotransmitters such as serotonin and ATP. This short article reviews the recent developments in the field with regard to glutamate receptors involved in both functions as well as the influence of glutamate on the taste signal., (© 2016 American Society for Nutrition.)

Taste buds are found on the tongue in 3 types of structures: the fungiform papillae, the foliate papillae, and the circumvallate papillae. Of these, the fungiform papillae (FP) are present in the greatest numbers on the tongue, and are thought to be correlated to the overall number of taste buds. For this reason, FP density on the tongue is often used to infer taste function, although this has been controversial. Historically, videomicroscopy techniques were used to assess FP. More recently, advances in digital still photography and in software have allowed the development of rapid methods for obtaining high quality images in situ. However, these can be subject to inter-researcher variation in FP identification, and are somewhat limited in the parameters that can be measured. Here, we describe the development of a novel, automated method to count the FP, using the TongueSim suite of software. Advantages include the reduction in time required for image analysis, elimination of researcher bias, and the added potential to measure characteristics such as the degree of roundness of each papilla. We envisage that such software has a wide variety of novel research applications., (© The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The aim of this study was to compare the anatomical and functional characteristics of the lingual papilla among the Camelidae. For this purpose, tongues of alpaca, guanaco, and llama were used. Numerous long and thin filiform papillae were located in the median groove and none were detected on the rest of the dorsal surface of the lingual apex in alpaca. Secondary papillae originated from the base of some filiform papillae on the ventral surface of alpaca tongue. The bases of some filiform papillae of the lateral surface of the lingual apex were inserted into conspicuous grooves in guanaco and tips of filiform papillae on the dorsal surface of the lingual body were ended by bifurcated apex. On the dorsal surface of the lingual apex of llama, there were no filiform papillae but there were numerous filiform papillae on both the lateral margins of the ventral surface of the lingual apex. Fungiform papillae were distributed randomly on dorsal lingual surface and ventral margins of the tongues of all camelid species. Lenticular papillae were located on the lingual torus and varied in size and topographical distribution for each species. Circumvallate papillae had irregular surfaces in llama and alpaca, and smooth surface in guanaco. In conclusion, llama and alpaca tongues were more similar to each other, and tongues of all camelid species displayed more similarities to those of Bactrian and dromedary camels in comparison with other herbivores and ruminants., (© 2015 Wiley Periodicals, Inc.)

As one of the adverse effects of oxaliplatin, a key agent in colon cancer chemotherapy, a taste disorder is a severe issue in a clinical situation because it decreases the quality of life of patients. However, there is little information on the mechanism underlying the oxaliplatin-induced taste disorder. Here, we examined the molecular and behavioral characteristics of the oxaliplatin-induced taste disorder in rats. Oxaliplatin (4-16 mg/kg) was administered to Sprague-Dawley (SD) rats intraperitoneally for 2 d. Expression levels of mRNA and protein of taste receptors in circumvallate papillae (CP) were measured by real-time quantitative polymerase chain reaction (PCR) and immunohistochemistry, respectively. Taste sensitivity was assessed by their behavioral change using a brief-access test. Morphological change of the taste buds in CP was evaluated by hematoxyline-eosin (HE) staining, and the number of taste cells in taste buds was counted by immunohistochemical analysis. Among taste receptors, the expression levels of mRNA and protein of T1R2, a sweet taste receptor subunit, were increased transiently in CP of oxaliplatin-administered rats on day 7. In a brief-access test, the lick ratio was decreased in oxaliplatin-administered rats on day 7 and the alteration was recovered to the control level on day 14. There was no detectable alteration in the morphology of taste buds, number of taste cells or plasma zinc level in oxaliplatin-administered rats. These results suggest that decreased sensitivity to sweet taste in oxaliplatin-administered rats is due, at least in part, to increased expression of T1R2, while these alterations are reversible.

Chimaeroid fishes are the only extant Holocephali, a subclass of Chondrichthyes. We describe for the first time a well evidenced structure localized in the palate of the chimaeroid Chimaera monstrosa, here named a palatal organ (PO). Attention has been paid to the holocephalan head morphology, but there has been no mention of this particular organ in the literature. The PO is a soft-tissue mass located within a slight hollow in between the two vomerine toothplates, and it protrudes into the oral cavity, resembling the mammalian incisive papilla. It is characterized by dense connective tissue with abundant collagen and elastic fibers and no muscular tissue. The robust innervation but low density of taste buds suggest a role in gustation for the PO, but primary utility in general mechanical sensitivity likely implicated in food sorting. The presence of numerous multicellular serous glands in the anterior/dorsal part of the PO is quite surprising because, in gnathostome fish, the presence of multicellular glands within the mouth has been reported in only the rare case of teeth-associated venom glands. Hypothesized roles for these glands could include food lubrication, digestion and defense against pathogens. In the literature, the presence of a PO has been demonstrated in many published images of chimaeroid fishes, but has gone unnoticed. This trait could represent a peculiar characteristic of all or a subset of holocephalans., (© 2015 Wiley Periodicals, Inc.)

The aim of this study was the description of the lingual and buccal papillae in adult alpaca (Vicugna pacos) by light and scanning electron microscopy (SEM). The tongue consisted of apex, body and root. Four types of lingual papillae (filiform, fungiform, conical and circumvallate) in addition to two types of buccal papillae were observed. The filiform papillae, some with secondary papillae, were distributed on both the corpus and apex of the tongue, with stratified epithelium, and layer of keratin coat were recognized. The short (small) cone papillae had pointed top, while bunoform papillae were wide with smooth apex. The much less numerous circumvallate papillae with pseudopapillae on the each rim of the caudal lingual body were present with weak layer of keratin and intra-epithelial taste buds. The small fungiform papillae were found on the dorsal lingual surface, while the large fungiform papillae were situated on the ventral surface of the tongue, especially, in rostral part and were round in shape with numerous gustatory pores and very thin keratin coat. Pseudopapillae were present on the buccal conical 'bunoform' papillae surface, while 'elongate' buccal papillae surface was rather softly folded with thin coat of keratin. Microridges were observed in the less keratinized parts of each type of papillae. The orientation of either lingual or buccal papillae into the throat side facilitates the emptying of oral cavity from nutrient and swallowing of food. In conclusion, the anatomical features of the alpaca tongue are an adaptation to the feeding habits., (© 2014 Blackwell Verlag GmbH.)

The goal of the Denver Papillae Protocol is to use a dichotomous key to define and prioritize the characteristics of fungiform papillae (FP) to ensure consistent scoring between scorers. This protocol builds off of a need that has arisen from the last two decades of taste research using FP as a proxy for taste pore density. FP density has historically been analyzed using Miller & Reedy's 1990 characterizations of their morphology: round, stained lighter, large, and elevated. In this work, the authors forewarned that stricter definitions of FP morphology needed to be outlined. Despite this call to action, follow up literature has been scarce, with most studies continuing to cite Miller & Reedy's original work. Consequently, FP density reports have been highly variable and, combined with small sample sizes, may contribute to the discrepant conclusions on the role of FP in taste sensitivity. The Genetics of Taste Lab explored this apparent inconsistency in counting and found that scorers were individually prioritizing the importance of these characteristics differently and had no guidance for when a papilla had some, but not all, of the reported qualities of FP. The result of this subjectivity is highly variable FP counts of the same tongue image. The Denver Papillae Protocol has been developed to remedy this consequence through use of a dichotomous key that further defines and prioritizes the importance of the characteristics put forth by Miller & Reedy. The proposed method could help create a standard way to quantify FP for researchers in the field of taste and nutritional studies.

The vomeronasal organ (VNO), also known as the Jacobson's organ, is a bilateral chemosensory organ found at the base of the nasal cavity specialized for the detection of higher-molecular weight (non-volatile) chemostimuli. It has been linked to pheromone detection. The VNO has been well studied in nocturnal lemurs and lorises, but poorly studied in diurnal/cathemeral species despite the large repertoire of olfactory behaviors noted in species such as Lemur catta. Here, the VNO and associated structures were studied microanatomically in one adult female and one adult male L. catta. Traditional and immunohistochemical procedures demonstrate the VNO epithelium consists of multiple rows of sensory neurons. Immunoreactivity to Growth-associated protein 43 (GAP43) indicates the VNO is postnatally neurogenic. In volume, the VNO neuroepithelium scales similarly to palatal length compared to nocturnal strepsirrhines. Numerous taste buds present at the oral opening to the nasopalatine duct, with which the VNO communicates, provide an additional (or alternative) explanation for the flehmen behavior that has been observed in this species. The VNO of L. catta is shown to be microanatomically comparable to that of nocturnal strepsirrhines. Like nocturnal strepsirrhines, the VNO of L. catta may be functional in the reception of high-molecular weight secretions., (© 2014 Wiley Periodicals, Inc.)

The epibranchial organ (EO) is an enigmatic tubular organ found in the pharyngeal cavity of many filter-feeding fishes. We investigated whether it might function as a taste organ that mediates aggregation and ingestion of planktonic food within the buccal cavity. The EO and associated structures of bighead and silver carps, two successful and invasive planktivorous fishes, were examined using histological and electrophysiological techniques. Both species possess finely structured gill rakers that extend directly via a series of protrusions into each of the four blind canals which are organized as the muscular EO, suggesting that the gill rakers and EO probably function in an integrated manner. Both the interior and exterior surfaces of the EOs of both species are covered with high densities of taste buds and solitary chemosensory cells (SCCs) as well as mucous cells. Conversely, taste buds are scarce in both the buccal cavities and external portions of the head and mouth of both species. Electrophysiological recordings from a caudal branch of the vagus nerve (cranial nerve X) found to innervate the EO showed it to be sensitive to chemicals found in a planktonic diet. l-Amino acids accounted for some, but not all of the neural activity. We conclude that taste buds and SCCs located on the EO and gill rakers probably serve to chemically detect food particles, which the EO then aggregates by mucus secretion before eventually expelling them onto the floor of the pharynx for ingestion. This specialized, pharyngeal chemosensory structure may explain the feeding success of these, and perhaps other planktivorous, filter-feeding fishes., (© 2014. Published by The Company of Biologists Ltd.)

The location and distribution of mucosal sensory structures of the crocodilian oral cavity are poorly understood. Although there are several descriptions of these structures in adults, nothing is known about their development. The purpose of this study was to document location, morphology, and relative abundance of these mucosal sensory structures in both hatchling and subadult alligators. Numerous mucosal sensory structures and pale staining dome-shaped papillae were observed only in the upper palate and tongue. In hatchlings, these papillae, which house either mechanoreceptive or chemosensory (taste buds) structures, were larger and more prevalent on the tongue than the upper palate. In the subadult, however, these papillae housed primarily mechanoreceptive structures and possibly degenerate taste buds. Although the presence of the mechanoreceptive structures in the palates of the suabadult alligator are to be expected, the loss of most taste buds is hitherto undocumented. Thus, there is morphological support for an ontogenetic shift in the role of the sensory palate, from a prey detection gustatory sensory system in hatchlings to a prey-manipulative mechanoreceptive system in subadults., (© 2014 Wiley Periodicals, Inc.)

Emerging evidence from a number of laboratories indicates that humans have the ability to identify fatty acids in the oral cavity, presumably via fatty acid receptors housed on taste cells. Previous research has shown that an individual's oral sensitivity to fatty acid, specifically oleic acid (C18:1) is associated with body mass index (BMI), dietary fat consumption, and the ability to identify fat in foods. We have developed a reliable and reproducible method to assess oral chemoreception of fatty acids, using a milk and C18:1 emulsion, together with an ascending forced choice triangle procedure. In parallel, a food matrix has been developed to assess an individual's ability to perceive fat, in addition to a simple method to assess fatty food liking. As an added measure tongue photography is used to assess papillae density, with higher density often being associated with increased taste sensitivity.

Recent reports suggest that polymorphisms in the carbonic anhydrase gene CA6 (also known as gustin) may explain additional variation in the bitterness of 6-n-propylthiouracil beyond that explained by variation in the bitter receptor gene TAS2R38. CA6 (gustin) has been implicated in taste bud function and salivary buffer capacity. In the present study we examined associations between polymorphisms in the CA6 gene with salt and bitter taste perception, and oral anatomy. 243 subjects (146 female) aged 18-45 rated the intensity of five concentrations of 6-n-propylthiouracil and NaCl on a generalized Labeled Magnitude Scale (gLMS) in duplicate and one concentration of potassium chloride (KCl). Using salivary DNA, we examined 12 SNPs within CA6 in relation to taste intensity and number of fungiform papillae. We observed no difference in bitter taste perception from 6-n-propylthiouracil (PROP) or from potassium chloride for any of the SNPs examined. Perceived saltiness of NaCl on the other hand was significantly associated with a number of CA6 polymorphisms, and particularly rs3737665. Nonetheless, FP density did not vary between alleles of rs3737665, nor with any of the other CA6 SNPs. Also, we fail to find any evidence that CA6 effects on taste perception are due to differences in fungiform papilla number. Additional work is needed to confirm whether variations within the CA6 gene may be responsible for differences in salt taste perception., (Copyright © 2014 Elsevier Inc. All rights reserved.)