Structure of taste buds in foliate papillae of the rhesus monkey, Macaca mulatta

Abstract

Taste buds in foliate papillae of the rhesus monkey were examined by electron microscopy. Three distinct cell types were identified. Type I cells were narrow elongated cells containing an oval nucleus, bundles of intermediate filaments, several Golgi bodies, and characteristic apical membrane-bounded dense granules. These cells exhibited morphological variations: some had a moderately dense cytoplasm, perinuclear free ribosomes, and flattened sacs of rough endoplasmic reticulum; others had a more lucent cytoplasm, dilated irregular rough endoplasmic reticulum, lysosome-like dense bodies, and lipid droplets. Type II cells typically contained a spherical, pale nucleus, a prominent nucleolus, supranuclear and infranuclear Golgi bodies, mitochondria with tubular cristae, and one or two centrioles. This cell type, too, showed some variation in the relative amounts of ribosomes and smooth endoplasmic reticulum, which varied inversely with each other. Type III cells were characterized by a clear apical cytoplasm essentially devoid of ribosomes and containing microtubules. In a few type III cells, the peri- and infranuclear regions contained many ribosomes and some rough endoplasmic reticulum. In most Type III cells, there were large numbers of dense and clear vesicles in the peri- and infranuclear regions; some of the vesicles were grouped in synapse-like arrangements with adjacent nerves. The morphological variations exhibited by all three cell types could be accounted for by age differences in each of the cells. This would be consistent with the notion that cell renewal occurs in each of the three cell populations.

Fine structure of the taste bud in guinea pigs. I. Cell characterization and innervation patterns.

“…Consequently, differentiated cells of the rabbit taste bud were classified into three groups, designated as type I (dark cell), type II (light cell), and type III (MURRAY, 1971). Cells with fine-structural features similar to those depicted by MURRAY and associates have since been described also in other mammalian species including man (PARAN et al, 1975), the rat (TAKEDA and HOSHINO, 1975), the mouse (TAKEDA, 1976), and the monkey FARBMAN et al, 1985).…”

“…As the features of each cell type essentially coincided with those already characterized in other species, the cells of the guinea pig taste bud were designated as: basal, type I, type II, and type III in accordance with the nomenclature proposed by MURRAY (1973) and used by later authors (TAKEDA and HOSHINO, 1975;TA-KEDA, 1976;FARBMAN et al, 1985). Additionally, the guinea pig taste buds also included degenerating bud cells and intrusive cells as well as nerve fibers which formed synapses or made other specialized contacts with certain types of cells.…”

“…In the rhysus monkey, IDE and MUNGER (1980) discriminated two cell types: sustentacular and chemosensory cells (see also ZAHM and MUNGER, 1983a, b), whereas FARBMAN et al (1985) (KIN-NAMON et al, 1985;see also DELAY et al, 1986;KINNAMON et al, 1988;ROYER and KINNAMON, 1988).…”

“…Individual taste buds have been described as showing a relatively simple organization, comprising several cell types, up to as many as five (FARBMAN, 1965a;MURRAY et al, 1969). On their ultrastructural bases, taste bud cells have been postulated to participate in either gustatory or supporting functions PARAN et al, 1975;TAKEDA and HOSHINO, 1975;TAKEDA, 1976;IDE and MUNGER, 1980;FARBMAN et al, 1985), although controversy has arisen over which cell type or types are gustatory and which are supporting in nature. KINNAMON et al (1985), in contrast, proposed that every differentiated cell in the mouse taste bud acts as a gustatory receptor (cf.…”

The Taste Bud and Its Innervation in the Rat as Studied by Immunohistochemistry for PGP 9.5.

“…The present study confirms in the rat that the taste bud consists of the Type I (supportive cell), Type II (sensory cell of unknown nature), Type III (gustatory cell) and Type IV or basal cell, as has been reported in different mammals (e.g., in the rabbit: MURRAY et al, 1969; in the human: PARAN et al, 1975;in the rat: TAKEDA and HOSHINO, 1975;in the mouse: TAKEDA, 1976; in the rhesus monkey: IDE andMUNGER, 1980 andFARBMAN et al, 1985; in the guinea pig: YOSHIE et al, 1990).…”