Exocytotic release of neurotransmitter substances from nerve endings in the taste buds of rat circumvallate papillae.

Endo, Yasuhisa

doi:10.1679/aohc.51.489

Cited by 11 publications

(4 citation statements)

References 14 publications

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“…Although synapses are not evident in this figure, 1 day old chick taste buds exhibit apparent afferent synapses (Ganchrow et al, 1991) at sites showing light cell-nerve fiber configurations similar to that shown in Figure 6A. The irregular configuration of the nerve fiber membrane indicated in Figure 6B resembles exocytotic figures identified in rat taste bud nerves (Endo, 1988).…”

Section: Resultssupporting

confidence: 53%

Aspects of vertebrate gustatory phylogeny: Morphology and turnover of chick taste bud cells

Ganchrow

Royer

et al. 1993

Microscopy Res & Technique

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The taste bud is a receptor form observed across vertebrates. The present report compares chick taste buds to those of other vertebrates using light and electron microscopy. Unlike mammals, but common to many modern avians, the dorsal surface of chick anterior tongue lacks taste papillae and taste buds. Ultrastructurally, chick buds located in the anterior floor of the mouth (as in some reptiles and amphibians) and palate contain dark, intermediate, light, and basal cell types. Dark, intermediate, and light cells extend microvilli into intragemmal lumina and pores communicating with the oral cavity. As specialized features, dark cell apices lack dense granules and exhibit short microvilli relative to light and intermediate cells. Dark cell cytoplasmic fingers envelop intragemmal nerve fibers and cells as in other species, and sometimes contain abundant clear vesicles. Nerve profile expansions often are located adjacent to dark, intermediate, and light cell nuclei. Classical afferent synaptic contacts are rarely observed. Taste cell turnover is suggested by mitotic and degenerating figures in chick buds. In addition, tritiated thymidine injected into hatchlings, whose anterior mandibular oral taste bud population approximates that in adults, reveals a turnover rate of about 4.5 days. This is about half that observed in altricial mammals, reflecting a species difference or developmental factor in precocial avians. It is concluded that chick taste buds exhibit morphologic features common to other vertebrate buds with specializations reflecting the influences of niche, glandular relations, and/or age.

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Section: Resultssupporting

confidence: 53%

Aspects of vertebrate gustatory phylogeny: Morphology and turnover of chick taste bud cells

Ganchrow

Royer

et al. 1993

Microscopy Res & Technique

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“…Interestingly, omega shaped images of clear vesicles, likely representing exocytotic release of transmitter, have been observed in nerve fibers abutting taste buds [52]. Type II "receptor" cells respond to taste stimulation by release of ATP, which activates purinergic receptors on afferent nerve fibers [23] and adjacent taste cells [24,53].…”

Section: Discussionmentioning

confidence: 99%

Evidence for a role of glutamate as an efferent transmitter in taste buds

et al. 2010

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BackgroundGlutamate has been proposed as a transmitter in the peripheral taste system in addition to its well-documented role as an umami taste stimulus. Evidence for a role as a transmitter includes the presence of ionotropic glutamate receptors in nerve fibers and taste cells, as well as the expression of the glutamate transporter GLAST in Type I taste cells. However, the source and targets of glutamate in lingual tissue are unclear. In the present study, we used molecular, physiological and immunohistochemical methods to investigate the origin of glutamate as well as the targeted receptors in taste buds.ResultsUsing molecular and immunohistochemical techniques, we show that the vesicular transporters for glutamate, VGLUT 1 and 2, but not VGLUT3, are expressed in the nerve fibers surrounding taste buds but likely not in taste cells themselves. Further, we show that P2X2, a specific marker for gustatory but not trigeminal fibers, co-localizes with VGLUT2, suggesting the VGLUT-expressing nerve fibers are of gustatory origin. Calcium imaging indicates that GAD67-GFP Type III taste cells, but not T1R3-GFP Type II cells, respond to glutamate at concentrations expected for a glutamate transmitter, and further, that these responses are partially blocked by NBQX, a specific AMPA/Kainate receptor antagonist. RT-PCR and immunohistochemistry confirm the presence of the Kainate receptor GluR7 in Type III taste cells, suggesting it may be a target of glutamate released from gustatory nerve fibers.ConclusionsTaken together, the results suggest that glutamate may be released from gustatory nerve fibers using a vesicular mechanism to modulate Type III taste cells via GluR7.

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“…Alternatively, dual axon contacts may indicate the transient interaction of afferent and possibly efferent sources during early receptogenesis. In general, axo-axonal profiles are not evident in adult chicken material (Ganchrow and Ganchrow, unpublished observations); they have been reported to be present primarily in early-to midgestational fetal macaques (Zahm and Munger, 1983a,b) and young postnatal rodents (Yamasaki and Tohyama, 1985;Ozeki, 1987;Endo, 1988), and during regenerative periods of taste-bud development (e.g., rabbit: Fujimoto and Murray, 1970). In addition, axoaxonal synapses have been reported in guinea pig (Yoshie et al, 1990) and tortoise (Uchida, 1980) taste buds (ages not specified).…”

Section: Discussionmentioning

confidence: 99%

Ultrastructure of palatal taste buds in the perihatching chick

Ganchrow¹,

Ganchrow²,

Goldstein³

1991

Am. J. Anat.

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Palatal taste buds of perihatching chicks were examined by electron microscopy. Four intragemmal cell types were characterized. 1) Light: with voluminous, electron-lucent cytoplasm containing scattered free ribosomes, rough and smooth endoplasmic reticulum, plump mitochondria, sparse perinuclear filaments, occasional Golgi bodies, and numerous clear and dense-cored vesicles. Clear vesicles sometimes aggregate in a presynaptic-like configuration apposed to an axonal profile. These cells contained large, spherical, uniformly granular nuclei with one nucleolus. 2) Dark: with dense cytoplasm containing filamentous bundles surrounding the nucleus, occasional clear vesicles, centrioles, rough endoplasmic reticulum, and compact mitochrondria. The apical cytoplasm noticeably lacks dense secretory granules. Irregular to lobulated nuclei are densely granular, and contain scattered clumps of chromatin, adhering especially to the inner leaflet of the nuclear membrane, and at least one nucleolus. Cytoplasmic extensions of dark cells envelop other intragemmal cell types and nerve fibers. Light and dark cells project microvilli into the taste pore. 3) Intermediate: contain gradations of features of light and dark cells. 4) Basal: darker than the other intragemmal cell types and confined to the ventral bud region. Putative afferent synapses in relation to light cells, and axo-axonal contacts are described. While the appearance of axo-axonal contacts may be a transient developmental event, other bud features are consonant with observations in adult chickens and suggest that the peripheral gustatory apparatus is mature at hatching in this precocial avian species.

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Exocytotic release of neurotransmitter substances from nerve endings in the taste buds of rat circumvallate papillae.

Cited by 11 publications

References 14 publications

Aspects of vertebrate gustatory phylogeny: Morphology and turnover of chick taste bud cells

Aspects of vertebrate gustatory phylogeny: Morphology and turnover of chick taste bud cells

Evidence for a role of glutamate as an efferent transmitter in taste buds

Ultrastructure of palatal taste buds in the perihatching chick

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