Neuron-specific enolase (NSE), a brain specific isoenzyme of the glycolytic enzyme, is characterized by its consistent occurrence in the cytoplasm of mature neurons. The purpose of the present study was to investigate the expression of NSE in the developing tongue of Korean native goats. The tongues of the fetuses were removed from 2- to 4-year-old female Korean native goats by caesarean section performed under general anesthesia. The expression of NSE in the developing tongue of goat fetuses (60, 90, 120, and 150 days) was studied using immunohistochemistry. In 60-day-old fetuses, NSE-immunoreactivity (IR) exhibited weak appearance in lamina propria of the basal portion and the apical epithelia of the tongue. In 90-day-old fetuses, NSE-nerve fibers were extended in the core part of connective tissue, and primordia of the taste buds was moderately positive. In 120-day-old fetuses, NSE-IR was strongly expressed in taste buds and gustatory nerve fibers. In neonates, the taste buds of vallate papillae were strongly positive for NSE, and development of nerve fibers was synapsed with connective tissue of well innervated taste buds. These results indicate that NSE expressions were associated with the sign of nerve innervation in prenatal development of goat tongues and NSE may be a useful neuronal marker to understand the development of gustatory nerve innervations.

The morphology of the lingual papillae in a female Bengal tiger (Panthera tigris tigris) was examined by scanning electron microscopy (SEM). The tongue was 22.3 cm in length and 7.1 cm in width. Numerous filiform papillae were distributed over the entire dorsal surface of the tongue. SEM examination of the tongue revealed two types of mechanical papillae, i.e. filiform and conical papilla, and two types of gustatory papillae, i.e. fungiform and vallate papilla, on the dorsal surface of the tongue. Each filiform papilla consisted of one primary papilla and several secondary papillae. The filiform papillae on the anterior part of the tongue were divided into one primary and 6~14 secondary papillae. Unlike other mammalians, however, secondary papillae in the mid-part of the tongue showed pineal-like papillae. In the posterior part of the tongue, secondary papillae were rare or absent. Fungiform papillae were surrounded by filiform papillae and densely distributed on the lingual surface. There were two vallate papillae on the borderline between the lingual body and root of the tongue. A vallate papilla contained two secondary papillae inside the grooves. Conical papillae were located in the area of the vallate papillae and covered the posterior part of the tongue root. No foliate papillae were seen on both margins of the posterior part of the tongue. Our results indicate that the structure on the lingual papillae of the Bengal tiger is somewhat different from that of other mammals.

Cytokeratin (CK) comprises the intermediate filament cytoskeleton of epithelial cells. Patterns of CK expression can be regarded as a specific marker for epithelial differentiation status. The aim of this study was to identify CK expression on tongues of Korean native goats ranging from 60-day-old fetuses to newborns during prenatal development using immunohistochemistry. The tongues of fetuses were removed from 2- to 4-year-old female Korean native goats by caesarean section performed under general anesthesia. Immunohistochemistry was performed to assess CK expression patterns on developing goat tongues using serial paraffin-embedded sections. Light zones signifying CK immunoreactivity in dorsal lingual epithelia were weakly positive in 60-day-old fetuses. In 90-day-old fetuses, deep areas in dorsal lingual epithelia were strongly positive for CK expression and superficial areas were moderately positive. In 120-day-old fetuses, light zones of lingual epithelia in the vallate papilla were strongly positive for CK expression, whereas ducts of von Ebner’s glands were moderately positive. In neonates, taste buds were positive for CK expression, whereas non-taste epithelial cells and von Ebner’s glands were negative. These findings indicate that goat tongues have different patterns of CK expression during development and provide a morphological basis for studies on the biological mechanism of epithelial differentiation.

The purpose of this study was to identify the composition and organization of lingual tissues underlying the histo-structural change of developing tongue in Korean native goats by light microscopy (LM). Tongues of the fetuses on days 60, 90, 120 and neonate were examined for the morphological development. In the 60-day-old fetuses, the tongue tissues were differentiated into epithelium, lamina propria and muscle layer. Primordia of filiform, conical, lentiform, fungiform and vallate papillae appeared and rudiments of taste bud were observed in the epithelia of the primordia of the gustatory papillae. The dorsal surface of the lingual epithelia showed a weak PAS positive reaction. Collagenous fibers and small blood vessels were shown in the connective tissues. In the 90-day-old fetuses, Von Ebner’s glands were moderately PAS positive while the muscle fibers and connective tissue were strongly positive for PAS. The collagenous fibers increased and came to have a more complex arrangement in the tongue. The muscle fibers were spread out at various directions and developed in striated muscle bundles. In the 120-day-old fetuses, taste buds were observed in the epithelia of the gustatory papillae, and several well-developed tissues visible such as blood vessels, collagenous fibers, muscle fiber bundles and Von Ebner’s glands. In the neonates, many taste buds were found in a transverse section of the vallate papilla. The muscle layers, Von Ebner’s glands, collagenous fibers and blood vessels were more developed than those of the 120-day old fetuses. These findings indicate that goat tongues have a variety of different shapes during prenatal development.

The purpose of this study was to explore the morphologi- cal characteristics of developing lentiform papilla (LP) in Korean native goats by scanning electron microscopy (SAM). Tongues were removed from fetuses on days 90, 120, neonates, and juveniles on days 30, 60, 90, 120, 150, and 180. In prenatal development, the primordia of LP in 90-day-old fetuses were round and spotted on the inner most part of the torus linguae of the tongue. Primordia of LP in 120-day-old fetuses also had a lens-like shape. In neonates, LP displayed similar features as the adult one. In postnatal juveniles on days 30 and 60, LP continually increased in size without much difference in structure compared to that of neonates. By postnatal day 90, detached pieces of keratinized super- ficial epithelia were observed. Microridges and microplicae were well developed on the epithelial surface of LP in 60- to 120-day-old goats. The lengths of LP were 476~514 μm in neonates, 687~962 μm in the weaning period of 60-day- old goats, and 1,068~1,567 μm in the maturing period of 180-day-old goats. These findings indicate that goat LP has different sizes and shapes from those of other species during development.

The aim of this study was to investigate the morphological development pattern of conical papilla (CP) during prenatal and postnatal periods in native Korean goats by scanning electron microscopy. Tongues were removed from fetuses on days 90, 120, and neonates and from juveniles on days 30, 50, 60, 75, 90, 120, 150, and 180 after birth. The lengths of CP were 194~240 μm in neonates, 335~485 μm in the weaning period of 60-day-old goats, and 526~662 μm in the maturing period of 180-day-old goats. The primordia of CP in 90-day-old fetuses, shaped like mountain berry, were sprouted. The CP of 120-day-old fetuses was a cylinder shape with an apex whose center was slightly concave and the margin was sticking up like a low fence. The CP of neonates was empty inside and the secondary papillae were irregularly arranged fence-like structures on it. In 60-day-old goats, CP was an obliquely sectioned cylinder shape compacted in inner surface; the shapes of CP varied in 120-day-old goats, and had a smooth surface. A low elevation of CP was observed in 150- and 180-day-old goats. The microridges, microplicae, and micropits were well developed on the epithelial surface of lingual papillae in 60- to 120-day-old goats. These findings indicate that CP of goats has a variety of sizes and shapes during development.

The purpose of the present study was to investigate the morphological characteristics of the developing vallate papillae (VP) of Korean native goats using scanning electron microscopy. In prenatal development of the VP, primordia of the VP were observed and the moat was shallowly spread in 60-day-old fetuses. The moat of the vallate papillae was shallowly spread and still undifferentiated in 90-day-old fetuses. The trench wall of the moat of the VP was well developed in 120-dayold fetuses. In neonates, the moat of the VP was more widely and deeply engraved and VP were developed as completely as those of adults. In postnatal development, VP were observed to have continually increased in size with slight morphological changes until 90-days after birth. Taste pores of the VP were shaped like flower leaves in 120-days after birth. The microridges and microplicaes were well developed on the epithelial surface of the VP in goats ranging from 120-day-old fetuses to 120-day-old postnatal animals. These results suppose that the sensing ability for gestation of VP was already well developed by the time of its birth and VP were differentiated into a variety of different shape and size during development.