Postnatal development of palatal and laryngeal taste buds in the hamster

Abstract

Mammalian taste buds are distributed within several distinct subpopulations, innervated by branches of three cranial nerves. These taste bud populations originate and mature at different times in various mammalian species and are thought to play differential roles in the control of taste-mediated behaviors. The hamster is a common animal for the electrophysiological study of the gustatory system, and it has been shown that taste buds innervated by the IXth nerve develop postnatally in this species. To delineate further the development of the gustatory system of hamsters, we quantified the number of taste buds appearing on the palatal, nasopharyngeal, and laryngeal epithelium from birth through 120 days of age. Taste buds are present in almost adult numbers on the soft palate at birth, but only 39% of these are mature. Distinct taste pores, indicative of mature taste buds, increase in number until about 20-30 days of life, at which time all of the taste buds on the soft palate and on the nasoincisive papillae are fully developed. Taste buds are concentrated primarily on the posterior and medial portions of the soft palate. Taste buds located on the laryngeal surface of the epiglottis and the aryepiglottal folds are absent at birth and originate and mature over the following 120 days. Laryngeal taste buds are more concentrated on the aryepiglottal folds than on the epiglottis. On the soft palate and in the epiglottal region, the maturation of taste buds is well characterized by a logarithmic function (Y = a log X + B) relating the number of mature taste buds to postnatal age. On the soft palate, the length of the taste buds from base to apex correlates with the thickness of the epithelium, which increases with development. The diameter of mature taste buds on the soft palate does not change with age. In contrast to many mammalian species, in rodents taste bud development occurs mostly after birth. Rapid postnatal development progresses at a time when ingestive behavior is undergoing a number of significant changes. Taste buds in the larynx have been implicated in a number of laryngeal reflexes (i.e., apnea, swallowing) in several nonrodent species. The electrophysiological properties of superior laryngeal nerve fibers would suggest a similar function for epiglottal taste buds in the hamster.

Brain‐derived neurotrophic factor‐, neurotrophin‐3‐, and tyrosine kinase receptor‐like immunoreactivity in lingual taste bud fields of mature hamster

“…Perhaps the key to the uniqueness of fiber IR in the fungiform bud field relates to the precocious development of fungiform buds in hamster. At birth, the adult complement of fungiform bud pores is already present (Whitehead and Kachele, 1994), in contrast to the postnatal development and maturation of foliate, circumvallate, palatal, and laryngeal buds (Miller and Smith, 1984;Belecky and Smith, 1990). The prominence of subgemmal TrkC-like fibers in mature hamster could reflect their possible earlier role in establishment of precocious fungiform buds or papillae.…”

Development and maturation of taste buds of the palatal epithelium of the rat: Histological and immunohistochemical study

“…The prenatal development of the palatal taste buds was traced in mammalian species such as humans, monkeys, sheep, and cats as well as hamsters (Bradley and Stern, 1967;Bradley et al, 1979;Stedman et al, 1983;Zahm and Munger, 1983;Belecky and Smith, 1990). The present study revealed that the development of rat taste buds is almost prenatal in the SP, whereas most entirely postnatal in the NIP.…”

Scanning Electron-Microscopic View of the Oral and Basal Epithelial Surfaces of the Rat Soft Palate

“…Taste plays an important role in the regulation of food intake, eliciting the basic response components of ingestion and aversion [Grill and Norgren, 1978;Belecky and Smith, 1990]. The taste buds of rats are distributed not only in the tongue but also in the pharynx, larynx and other regions of the oral cavity [Travers and Nicklas, 1990].…”