Sensory - Taste Development: Difference between revisions

From Embryology
Line 14: Line 14:
|-bgcolor="F5FAFF"  
|-bgcolor="F5FAFF"  
|
|
* '''Developing a sense of taste'''<ref name=PMID23182899><pubmed>23182899</pubmed></ref> "Taste buds are found in a distributed array on the tongue surface, and are innervated by cranial nerves that convey taste information to the brain. For nearly a century, taste buds were thought to be induced by nerves late in embryonic development. However, this view has shifted dramatically. A host of studies now indicate that taste bud development is initiated and proceeds via processes that are nerve-independent, occur long before birth, and governed by cellular and molecular mechanisms intrinsic to the developing tongue. Here we review the state of our understanding of the molecular and cellular regulation of taste bud development, incorporating important new data obtained through the use of two powerful genetic systems, mouse and zebrafish."
* '''FGF Signaling Regulates the Number of Posterior Taste Papillae by Controlling Progenitor Field Size'''<ref><pubmed>21655085</pubmed>| [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3107195 PMC3107195] | http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1002098 PLoS Genetics]</ref> "The sense of taste is fundamental to our ability to ingest nutritious substances and to detect and avoid potentially toxic ones. Sensory taste buds are housed in papillae that develop from epithelial placodes. Three distinct types of gustatory papillae reside on the rodent tongue: small fungiform papillae are found in the anterior tongue, whereas the posterior tongue contains the larger foliate papillae and a single midline circumvallate papilla (CVP). Despite the great variation in the number of CVPs in mammals, its importance in taste function, and its status as the largest of the taste papillae, very little is known about the development of this structure. Here, we report that a balance between Sprouty (Spry) genes and Fgf10, which respectively antagonize and activate receptor tyrosine kinase (RTK) signaling, regulates the number of CVPs. Deletion of Spry2 alone resulted in duplication of the CVP as a result of an increase in the size of the placode progenitor field, and Spry1(-/-);Spry2(-/-) embryos had multiple CVPs, demonstrating the redundancy of Sprouty genes in regulating the progenitor field size. By contrast, deletion of Fgf10 led to absence of the CVP, identifying FGF10 as the first inductive, mesenchyme-derived factor for taste papillae. Our results provide the first demonstration of the role of epithelial-mesenchymal FGF signaling in taste papilla development, indicate that regulation of the progenitor field size by FGF signaling is a critical determinant of papilla number, and suggest that the great variation in CVP number among mammalian species may be linked to levels of signaling by the FGF pathway."
* '''FGF Signaling Regulates the Number of Posterior Taste Papillae by Controlling Progenitor Field Size'''<ref><pubmed>21655085</pubmed>| [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3107195 PMC3107195] | http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1002098 PLoS Genetics]</ref> "The sense of taste is fundamental to our ability to ingest nutritious substances and to detect and avoid potentially toxic ones. Sensory taste buds are housed in papillae that develop from epithelial placodes. Three distinct types of gustatory papillae reside on the rodent tongue: small fungiform papillae are found in the anterior tongue, whereas the posterior tongue contains the larger foliate papillae and a single midline circumvallate papilla (CVP). Despite the great variation in the number of CVPs in mammals, its importance in taste function, and its status as the largest of the taste papillae, very little is known about the development of this structure. Here, we report that a balance between Sprouty (Spry) genes and Fgf10, which respectively antagonize and activate receptor tyrosine kinase (RTK) signaling, regulates the number of CVPs. Deletion of Spry2 alone resulted in duplication of the CVP as a result of an increase in the size of the placode progenitor field, and Spry1(-/-);Spry2(-/-) embryos had multiple CVPs, demonstrating the redundancy of Sprouty genes in regulating the progenitor field size. By contrast, deletion of Fgf10 led to absence of the CVP, identifying FGF10 as the first inductive, mesenchyme-derived factor for taste papillae. Our results provide the first demonstration of the role of epithelial-mesenchymal FGF signaling in taste papilla development, indicate that regulation of the progenitor field size by FGF signaling is a critical determinant of papilla number, and suggest that the great variation in CVP number among mammalian species may be linked to levels of signaling by the FGF pathway."
* '''Fate mapping of mammalian embryonic taste bud progenitors'''<ref><pubmed>19363153</pubmed></ref>"Mammalian taste buds have properties of both epithelial and neuronal cells, and are thus developmentally intriguing. Taste buds differentiate at birth within epithelial appendages, termed taste papillae, which arise at mid-gestation as epithelial thickenings or placodes. ...we demonstrate that Shh-expressing embryonic taste placodes are taste bud progenitors, which give rise to at least two different adult taste cell types, but do not contribute to taste papillae. Strikingly, placodally descendant taste cells disappear early in adult life."
* '''Fate mapping of mammalian embryonic taste bud progenitors'''<ref><pubmed>19363153</pubmed></ref>"Mammalian taste buds have properties of both epithelial and neuronal cells, and are thus developmentally intriguing. Taste buds differentiate at birth within epithelial appendages, termed taste papillae, which arise at mid-gestation as epithelial thickenings or placodes. ...we demonstrate that Shh-expressing embryonic taste placodes are taste bud progenitors, which give rise to at least two different adult taste cell types, but do not contribute to taste papillae. Strikingly, placodally descendant taste cells disappear early in adult life."
|}
|}
[[Talk:Sensory_-_Taste_Development|Recent References]] | [[#References|References]]


==Development Timing==
==Development Timing==

Revision as of 10:49, 15 January 2013

Introduction

Tongue taste map[1]
Gustatory system neuroanatomy[2]

These notes introduce the development of the sense of taste which can divided into five basic tastes: bitter, salty, sweet, umami (savoury) and sour. Current research appears to have displaced the historic concept of a tongue "map".

A study in rat suggests that neonatal changes in circumvallate papillae may result in postnatal changes in "taste".[3] In frogs, a large taste disc (TD) is the largest vertebrate gustatory organ. Postnatally, the sense of taste is also closely related to the sense of smell.

Taste Links: Introduction | Student project | Tongue Development | Category:Taste
Historic Taste 
Historic Embryology: 1888 human infant papilla foliata | 1889 man taste-organs | Paper - Further observations on the development of the taste-organs of man|1889 further man taste-organs]]
Senses Links: Introduction | placode | Hearing and Balance hearing | balance | vision | smell | taste | touch | Stage 22 | Category:Sensory

| original page

Some Recent Findings

  • Developing a sense of taste[4] "Taste buds are found in a distributed array on the tongue surface, and are innervated by cranial nerves that convey taste information to the brain. For nearly a century, taste buds were thought to be induced by nerves late in embryonic development. However, this view has shifted dramatically. A host of studies now indicate that taste bud development is initiated and proceeds via processes that are nerve-independent, occur long before birth, and governed by cellular and molecular mechanisms intrinsic to the developing tongue. Here we review the state of our understanding of the molecular and cellular regulation of taste bud development, incorporating important new data obtained through the use of two powerful genetic systems, mouse and zebrafish."
  • FGF Signaling Regulates the Number of Posterior Taste Papillae by Controlling Progenitor Field Size[5] "The sense of taste is fundamental to our ability to ingest nutritious substances and to detect and avoid potentially toxic ones. Sensory taste buds are housed in papillae that develop from epithelial placodes. Three distinct types of gustatory papillae reside on the rodent tongue: small fungiform papillae are found in the anterior tongue, whereas the posterior tongue contains the larger foliate papillae and a single midline circumvallate papilla (CVP). Despite the great variation in the number of CVPs in mammals, its importance in taste function, and its status as the largest of the taste papillae, very little is known about the development of this structure. Here, we report that a balance between Sprouty (Spry) genes and Fgf10, which respectively antagonize and activate receptor tyrosine kinase (RTK) signaling, regulates the number of CVPs. Deletion of Spry2 alone resulted in duplication of the CVP as a result of an increase in the size of the placode progenitor field, and Spry1(-/-);Spry2(-/-) embryos had multiple CVPs, demonstrating the redundancy of Sprouty genes in regulating the progenitor field size. By contrast, deletion of Fgf10 led to absence of the CVP, identifying FGF10 as the first inductive, mesenchyme-derived factor for taste papillae. Our results provide the first demonstration of the role of epithelial-mesenchymal FGF signaling in taste papilla development, indicate that regulation of the progenitor field size by FGF signaling is a critical determinant of papilla number, and suggest that the great variation in CVP number among mammalian species may be linked to levels of signaling by the FGF pathway."
  • Fate mapping of mammalian embryonic taste bud progenitors[6]"Mammalian taste buds have properties of both epithelial and neuronal cells, and are thus developmentally intriguing. Taste buds differentiate at birth within epithelial appendages, termed taste papillae, which arise at mid-gestation as epithelial thickenings or placodes. ...we demonstrate that Shh-expressing embryonic taste placodes are taste bud progenitors, which give rise to at least two different adult taste cell types, but do not contribute to taste papillae. Strikingly, placodally descendant taste cells disappear early in adult life."

Recent References | References

Development Timing

These are human embryonic timings[7], not clinical which is based on last menstral period +2 weeks (GA).

Week 6 - gustatory papilla, caudal midline near the foramen caecum

Week 6-7 - nerve fibers approach the lingual epithelium

Week 8 - nerves penetrate epitheilai basal lamina and synapse with undifferentiated, elongated, epithelial cells (taste bud progenitor cell)

Week 10 - shallow grooves above the taste bud primordium

Week 12 - first differentiated epithelial cells (Type II and III)

Week 12 -13 - maximum synapses between cells and afferent nerve fibers

Week 14 - 15 - taste pores develop, mucous

Week 18 - substance P detected in dermal papillae, not in taste bud primordia

3rd Trimester -

Tongue Development

Neonatal rat tongue

Gustatory cranial sensory neurons

Cranial nerves VII, IX and X have dual embryonic origins and provide both gustatory (taste) and non-gustatory (touch, pain, temperature) sensory innervation to the oral cavity of vertebrates.

Gustatory Neurons

  • originate from epibranchial placodes
  • innervate taste buds
  • project centrally to the rostral nucleus of the solitary tract (NTS)

General Epithelial Innervation of the oral cavity

  • originate from cranial neural crest
  • innervation to the oropharynx
  • project to non-gustatory hindbrain regions (spinal trigeminal nucleus)

(text based on: Embryonic origin of gustatory cranial sensory neurons.[8])

Stage 22

Stage 22 image 060.jpg

Section (B4) through head showing tongue and head structures.

References

  1. <pubmed>17108952</pubmed>
  2. <pubmed>17903280</pubmed>
  3. <pubmed>11474141</pubmed>
  4. <pubmed>23182899</pubmed>
  5. <pubmed>21655085</pubmed>| PMC3107195 | http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1002098 PLoS Genetics]
  6. <pubmed>19363153</pubmed>
  7. <pubmed>8955790</pubmed>
  8. <pubmed>17826760</pubmed>


Reviews

<pubmed>21184814</pubmed> <pubmed>20696704</pubmed>| JCB

Articles

Search PubMed

Search May 2010

  • Taste System Development - All (320) Review (64) Free Full Text (78)
  • Tongue Development - All (2804) Review (258) Free Full Text (519)

Search Pubmed: Taste System Development | Tongue Development

Additional Images

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Cite this page: Hill, M.A. (2024, March 28) Embryology Sensory - Taste Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Sensory_-_Taste_Development

What Links Here?
© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G