2.Development and homeostasis of taste buds in mammals.
Xin ZHENG ; Xin XU ; Jin-Zhi HE ; Ping ZHANG ; Jiao CHEN ; Xue-Dong ZHOU
West China Journal of Stomatology 2018;36(5):552-558
Taste is mediated by multicellular taste buds distributed throughout the oral and pharyngeal cavities. The taste buds can detect five basic tastes: sour, sweet, bitter, salty and umami, allowing mammals to select nutritious foods and avoid the ingestion of toxic and rotten foods. Once developed, the taste buds undergo continuous renewal throughout the adult life. In the past decade, significant progress has been achived in delineating the cellular and molecular mechanisms governing taste buds development and homeostasis. With this knowledges and in-depth investigations in the future, we can achieve the precise management of taste dysfunctions such as dysgeusia and ageusia.
Animals
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Food
;
Homeostasis
;
Mammals
;
Taste
;
Taste Buds
;
growth & development
3.Immunohistochemical study on the dopaminergic and norepinephrinergic taste cells in rat taste buds.
Korean Journal of Anatomy 1998;31(2):293-298
Immunohistochemistry was applied to rat circumvallate papilla to localize the dopamine and norepinephrine in taste bud and to investigate the effect of preloading L-DOPA, dopamine and norepinephrine into taste cells. Dopamine and norepinephrine immunohistochemistry demonstrated that two to four taste cells except basal cells were weakly immunopositive for these neurotransmitters. Immunoreactive cells were elongated and their cell processes extended from the taste pore to the base of the taste bud. After pretreating animals with L-DOPA, four to six taste bud cells showed strong immunoreactivity for dopamine, but weak immunoreactivity for norepinephrine. Administration of dopamine or norepinephrine did not alter the number or intensity of immunoreactive cells in taste bud. These findings indicated that mammalian taste cells normally contain dopamine and norepinephrine, and that taste cells can take up L-DOPA and convert it to dopamine. Based on these findings, we postulate that norepinephrine functions as neurotransmitters or neuromodulators in taste sensory transmission.
Animals
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Dopamine
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Immunohistochemistry
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Levodopa
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Neurotransmitter Agents
;
Norepinephrine
;
Rats*
;
Taste Buds*
4.Ultrastructure of the taste pores and taste pits of human taste buds.
Yang MENG ; Zhuan BIAN ; Shuo-zhi WANG ; Qin LI ; Zhao-zhao HUANG
Chinese Journal of Stomatology 2006;41(12):762-763
OBJECTIVETo observe the ultrastructural features of taste pores and taste pits of human taste buds.
METHODSThree samplers obtained randomly from adults were divided into two perts, and transmission electron microscopy and scanning electron microscopy were used to observe the fine structure of taste buds in human circumvallate papillae.
RESULTSThe longer diameter of the taste pores was 1.02 - 7.36 microm, and most of taste pores contained no taste hair and dense material, and the profile of taste pit was triangular.
CONCLUSIONSTaste hair and dense material were seldom observed in most of taste pores.
Adult ; Humans ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Taste Buds ; ultrastructure ; Taste Perception ; Tongue ; ultrastructure
5.Regulation effect of lipopolysaccharide on the alternative splicing and function of sweet taste receptor T1R2.
Jian-Hui ZHU ; Xin ZHENG ; Xian PENG ; Xin XU ; Robert MARGOLSKEE ; Xue-Dong ZHOU
West China Journal of Stomatology 2021;39(4):469-474
OBJECTIVES:
To identify the alternative splicing isoform of mouse sweet taste receptor T1R2, and investigate the effect of lipopolysaccharide (LPS) local injection on T1R2 alternative splicing and the function of sweet taste receptor as one of the bacterial virulence factors.
METHODS:
After mouse taste bud tissue isolation was conducted, RNA extraction and reverse transcription polymerase chain reaction (PCR) were performed to identify the splicing isoform of T1R2. Heterologous expression experiments
RESULTS:
T1R2 splicing isoform T1R2_Δe3p formed sweet taste receptors with T1R3, which could not be activated by sweet taste stimuli and significantly downregulated the function of canonical T1R2/T1R3. Local LPS injection significantly increased the expression ratio of T1R2_Δe3p in mouse taste buds.
CONCLUSIONS
LPS stimulation affects the alternative splicing of mouse sweet taste receptor T1R2 and significantly upregulates the expression of non-functional isoform T1R2_Δe3p, suggesting that T1R2 alternative splicing regulation may be one of the mechanisms by which microbial infection affects host taste perception.
Alternative Splicing
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Animals
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Lipopolysaccharides
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Mice
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Receptors, G-Protein-Coupled/metabolism*
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Taste
;
Taste Buds
6.Progress in the effects of injury and regeneration of gustatory nerves on the taste functions in animals.
Yuan-Yuan FAN ; jpyan@xjtu.edu.cn. ; Dong-Ming YU ; Yu-Juan SHI ; Jian-Qun YAN ; En-She JIANG
Acta Physiologica Sinica 2014;66(5):519-527
The sensor of the taste is the taste bud. The signals originated from the taste buds are transmitted to the central nervous system through the gustatory taste nerves. The chorda tympani nerve (innervating the taste buds of the anterior tongue) and glossopharyngeal nerve (innervating the taste buds of the posterior tongue) are the two primary gustatory nerves. The injuries of gustatory nerves cause their innervating taste buds atrophy, degenerate and disappear. The related taste function is also impaired. The impaired taste function can be restored after the gustatory nerves regeneration. The rat model of cross-regeneration of gustatory nerves is an important platform for research in the plasticity of the central nervous system. The animal behavioral responses and the electrophysiological properties of the gustatory nerves have changed a lot after the cross-regeneration of the gustatory nerves. The effects of the injury, regeneration and cross-regeneration of the gustatory nerves on the taste function in the animals will be discussed in this review. The prospective studies on the animal model of cross-regeneration of gustatory nerves are also discussed in this review. The study on the injury, regeneration and cross-regeneration of the gustatory nerves not only benefits the understanding of mechanism for neural plasticity in gustatory nervous system, but also will provide theoretical basis and new ideas for seeking methods and techniques to cure dysgeusia.
Animals
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Chorda Tympani Nerve
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physiology
;
Glossopharyngeal Nerve
;
physiology
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Nerve Regeneration
;
Neuronal Plasticity
;
Rats
;
Taste
;
physiology
;
Taste Buds
;
physiology
;
Tongue
;
innervation
7.METTL3-mediated m6A RNA methylation regulates dorsal lingual epithelium homeostasis.
Qiuchan XIONG ; Caojie LIU ; Xin ZHENG ; Xinyi ZHOU ; Kexin LEI ; Xiaohan ZHANG ; Qian WANG ; Weimin LIN ; Ruizhan TONG ; Ruoshi XU ; Quan YUAN
International Journal of Oral Science 2022;14(1):26-26
The dorsal lingual epithelium, which is composed of taste buds and keratinocytes differentiated from K14+ basal cells, discriminates taste compounds and maintains the epithelial barrier. N6-methyladenosine (m6A) is the most abundant mRNA modification in eukaryotic cells. How METTL3-mediated m6A modification regulates K14+ basal cell fate during dorsal lingual epithelium formation and regeneration remains unclear. Here we show knockout of Mettl3 in K14+ cells reduced the taste buds and enhanced keratinocytes. Deletion of Mettl3 led to increased basal cell proliferation and decreased cell division in taste buds. Conditional Mettl3 knock-in mice showed little impact on taste buds or keratinization, but displayed increased proliferation of cells around taste buds in a protective manner during post-irradiation recovery. Mechanically, we revealed that the most frequent m6A modifications were enriched in Hippo and Wnt signaling, and specific peaks were observed near the stop codons of Lats1 and FZD7. Our study elucidates that METTL3 is essential for taste bud formation and could promote the quantity recovery of taste bud after radiation.
Animals
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Epithelium/metabolism*
;
Homeostasis
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Methylation
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Methyltransferases/metabolism*
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Mice
;
RNA
;
Taste Buds/metabolism*
8.Sweet Taste-Sensing Receptors Expressed in Pancreatic beta-Cells: Sweet Molecules Act as Biased Agonists.
Itaru KOJIMA ; Yuko NAKAGAWA ; Yoshiaki OHTSU ; Anya MEDINA ; Masahiro NAGASAWA
Endocrinology and Metabolism 2014;29(1):12-19
The sweet taste receptors present in the taste buds are heterodimers comprised of T1R2 and T1R3. This receptor is also expressed in pancreatic beta-cells. When the expression of receptor subunits is determined in beta-cells by quantitative reverse transcription polymerase chain reaction, the mRNA expression level of T1R2 is extremely low compared to that of T1R3. In fact, the expression of T1R2 is undetectable at the protein level. Furthermore, knockdown of T1R2 does not affect the effect of sweet molecules, whereas knockdown of T1R3 markedly attenuates the effect of sweet molecules. Consequently, a homodimer of T1R3 functions as a receptor sensing sweet molecules in beta-cells, which we designate as sweet taste-sensing receptors (STSRs). Various sweet molecules activate STSR in beta-cells and augment insulin secretion. With regard to intracellular signals, sweet molecules act on STSRs and increase cytoplasmic Ca2+ and/or cyclic AMP (cAMP). Specifically, when an STSR is stimulated by one of four different sweet molecules (sucralose, acesulfame potassium, sodium saccharin, or glycyrrhizin), distinct signaling pathways are activated. Patterns of changes in cytoplasmic Ca2+ and/or cAMP induced by these sweet molecules are all different from each other. Hence, sweet molecules activate STSRs by acting as biased agonists.
Bias (Epidemiology)*
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Calcium
;
Cyclic AMP
;
Cytoplasm
;
Insulin
;
Polymerase Chain Reaction
;
Potassium
;
Reverse Transcription
;
RNA, Messenger
;
Saccharin
;
Sodium
;
Taste Buds
9.Morphological evidences in circumvallate papilla and von Ebners' gland development in mice.
Wern Joo SOHN ; Gi Jeong GWON ; Chang Hyeon AN ; Cheil MOON ; Yong Chul BAE ; Hitoshi YAMAMOTO ; Sanggyu LEE ; Jae Young KIM
Anatomy & Cell Biology 2011;44(4):274-283
In rodents, the circumvallate papilla (CVP), with its underlying minor salivary gland, the von Ebners' gland (VEG), is located on the dorsal surface of the posterior tongue. Detailed morphological processes to form the proper structure of CVP and VEG have not been properly elucidated. In particular, the specific localization patterns of taste buds in CVP and the branching formation of VEG have not yet been elucidated. To understand the developmental mechanisms underlying CVP and VEG formation, detailed histological observations of CVP and VEG were examined using a three-dimensional computer-aided reconstruction method with serial histological sections and pan-Cytokeratins immunostainings. In addition, to define the developmental processes in CVP and VEG formation, we examined nerve innervations and cell proliferation using microinjections of AM1-43 and immunostainings with various markers, including phosphoinositide 3-kinase, Ki-67, PGP9.5, and Ulex europaeus agglutinin 1 (UEA1). Results revealed specific morphogenesis of CVP and VEG with nerve innervations patterns, evaluated by the coincided localization patterns of AM1-43 and UEA1. Based on these morphological and immunohistochemical results, we suggest that nerve innervations and cell proliferations play important roles in the positioning of taste buds in CVP and branching morphogenesis of VEG in tongue development.
Animals
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Cell Proliferation
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Mice
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Microinjections
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Morphogenesis
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Rodentia
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Salivary Glands, Minor
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Taste Buds
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Tongue
;
Ulex
;
von Ebner Glands
10.Immuno-electronmicroscopic study on the serotoninergic taste cells and calcitonin gene-related peptide nerve fibers in mouse taste buds.
Korean Journal of Anatomy 1999;32(2):143-152
To investigate the distribution, ultrastructure and synapsis of serotoninergic cells and CGRP nerve fibers in mammalian taste buds, immunohistochemistry and electronmicroscopy were applied to mice vallate papillae. In normal mice, 1~2 serotonin immunoreactive cells were present in each taste bud section. After preloading 5-HTP, 3~6 cells showed strong immunoreactivity for serotonin. These cells were elongated, and their cytoplasm extended from the taste pore to the base of the taste bud. CGRP nerve fibers formed thick subgemmal nerve plexus under the basal lamina, and branched varicose perigemmal and intragemmal nerve fibers. Under the electron-microscope, three types of taste cells; dark cell, light cell and basal cells, were identified by their shape, location and electrical densities. Immuno-electronmicroscopy revealed that serotoninergic cells were dark cells. CGRP nerve fibers were located in and around taste buds, but the synaptic contacts with taste cells was not found. These findings indicate that mice taste cells are consisted of dark cell, light cell and basal cells, and dark cells contain serotonin. And, CGRP nerve fibers in taste buds may function as general sensory fibers.
5-Hydroxytryptophan
;
Animals
;
Basement Membrane
;
Calcitonin Gene-Related Peptide*
;
Calcitonin*
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Chromosome Pairing
;
Cytoplasm
;
Immunohistochemistry
;
Mice*
;
Nerve Fibers*
;
Serotonin
;
Taste Buds*