Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (677 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
A cartilaginous rod of mesodermal cells at the dorsal midline of all chordate embryos. In lower vertebrates, notochord is the backbone of support. In the higher vertebrates, notochord is a transient structure, and segments of the vertebral column will develop around it. Notochord is also a source of midline signals that pattern surrounding tissues including the neural tube development.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Notochords; Chordamesoderm; Chordamesoderms.
Where it fits in the MeSH classification
- Broader topics
- Embryonic Structures
Related concepts
- Chordate
- Neural Tube
Research landscape
PubMed indexes 1,779 records tagged with the MeSH heading “Notochord” (counts retrieved 2026-10-31). 173 of them (9.7%) were published from 2020 onward, and the busiest period so far is through 1999 with 686 records.
Reviews account for 161 records (9.1%) and meta-analyses for 0. Randomized controlled trials number 0 (0.0%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 686 |
| 2000-2009 | 486 |
| 2010-2019 | 434 |
| 2020 onward | 173 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 161 | 9.1% |
| Meta-analyses | 0 | 0.0% |
| Randomized controlled trials | 0 | 0.0% |
Method: PubMed query "Notochord"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Damage-induced reactive oxygen species enable zebrafish tail regeneration by repositioning of Hedgehog expressing cells | 2018 | Research article Design not recorded in structured metadata | 81 | cc by PMID 30275454 · DOI · PMC6167316 |
| Segmentation of the zebrafish axial skeleton relies on notochord sheath cells and not on the segmentation clock | 2018 | Research article Design not recorded in structured metadata | 74 | cc by PMID 29624170 · DOI · PMC5962341 |
| Variable combinations of specific ephrin ligand/Eph receptor pairs control embryonic tissue separation | 2014 | Research article Design not recorded in structured metadata | 67 | cc by PMID 25247423 · DOI · PMC4172438 |
| Coupling Vgll4b/Yap-regulated posterior cell addition with anterior vacuolation enables robust notochord elongation | 2026 | Research article Design not recorded in structured metadata | 0 | cc by PMID 42596839 · DOI · PMC13615686 |
Damage-induced reactive oxygen species enable zebrafish tail regeneration by repositioning of Hedgehog expressing cells [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Many aquatic vertebrates have a remarkable ability to regenerate limbs and tails after amputation.
- Closing excerpt
- Our results provide a model for how ROS initiate tail regeneration, and indicate that developmental signalling pathways can play regenerative functions that are not directly related to their developmental roles.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (149 words)
Many aquatic vertebrates have a remarkable ability to regenerate limbs and tails after amputation. Previous studies indicate that reactive oxygen species (ROS) signalling initiates regeneration, but the mechanism by which this takes place is poorly understood. Developmental signalling pathways have been shown to have proregenerative roles in many systems. However, whether these are playing roles that are specific to regeneration, or are simply recapitulating their developmental functions is unclear. Here, we analyse zebrafish larval tail regeneration and find evidence that ROS released upon wounding cause repositioning of notochord cells to the damage site. These cells secrete Hedgehog ligands that are required for regeneration. Hedgehog signalling is not required for normal tail development suggesting that it has a regeneration-specific role. Our results provide a model for how ROS initiate tail regeneration, and indicate that developmental signalling pathways can play regenerative functions that are not directly related to their developmental roles.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 30275454 · DOI · PMC6167316
Segmentation of the zebrafish axial skeleton relies on notochord sheath cells and not on the segmentation clock [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Segmentation of the axial skeleton in amniotes depends on the segmentation clock, which patterns the paraxial mesoderm and the sclerotome.
- Closing excerpt
- This behavior is not consistent with a clock-type mechanism in the notochord.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (142 words)
Segmentation of the axial skeleton in amniotes depends on the segmentation clock, which patterns the paraxial mesoderm and the sclerotome. While the segmentation clock clearly operates in teleosts, the role of the sclerotome in establishing the axial skeleton is unclear. We severely disrupt zebrafish paraxial segmentation, yet observe a largely normal segmentation process of the chordacentra. We demonstrate that axial entpd5+ notochord sheath cells are responsible for chordacentrum mineralization, and serve as a marker for axial segmentation. While autonomous within the notochord sheath, entpd5 expression and centrum formation show some plasticity and can respond to myotome pattern. These observations reveal for the first time the dynamics of notochord segmentation in a teleost, and are consistent with an autonomous patterning mechanism that is influenced, but not determined by adjacent paraxial mesoderm. This behavior is not consistent with a clock-type mechanism in the notochord.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 29624170 · DOI · PMC5962341
Variable combinations of specific ephrin ligand/Eph receptor pairs control embryonic tissue separation [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Ephrins and Eph receptors are involved in the establishment of vertebrate tissue boundaries.
- Closing excerpt
- These results provide a paradigm for how developmental systems may integrate multiple cues to generate discrete local outcomes.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (203 words)
Ephrins and Eph receptors are involved in the establishment of vertebrate tissue boundaries. The complexity of the system is puzzling, however in many instances, tissues express multiple ephrins and Ephs on both sides of the boundary, a situation that should in principle cause repulsion between cells within each tissue. Although co-expression of ephrins and Eph receptors is widespread in embryonic tissues, neurons, and cancer cells, it is still unresolved how the respective signals are integrated into a coherent output. We present a simple explanation for the confinement of repulsion to the tissue interface: Using the dorsal ectoderm-mesoderm boundary of the Xenopus embryo as a model, we identify selective functional interactions between ephrin-Eph pairs that are expressed in partial complementary patterns. The combined repulsive signals add up to be strongest across the boundary, where they reach sufficient intensity to trigger cell detachments. The process can be largely explained using a simple model based exclusively on relative ephrin and Eph concentrations and binding affinities. We generalize these findings for the ventral ectoderm-mesoderm boundary and the notochord boundary, both of which appear to function on the same principles. These results provide a paradigm for how developmental systems may integrate multiple cues to generate discrete local outcomes.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 25247423 · DOI · PMC4172438
Coupling Vgll4b/Yap-regulated posterior cell addition with anterior vacuolation enables robust notochord elongation [4]
Abstract reading summary — source excerpts
- Opening excerpt
- Robust tissue growth control requires long-range communication between the rate of progenitor addition and tissue expansion.
- Closing excerpt
- These results support a long-range feedback mechanism linking progenitor recruitment to vacuolation, enabling the notochord to balance cellular input with volumetric expansion, thereby maintaining tissue proportions.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (183 words)
Robust tissue growth control requires long-range communication between the rate of progenitor addition and tissue expansion. However, the regulatory mechanisms that couple these processes are unknown. In zebrafish, notochord morphogenesis is a driver of axis extension through both posterior progenitor addition and anterior vacuolation. To elucidate how progenitor dynamics and vacuole-driven cell expansion interact to elongate the notochord, we generated a mathematical model linking progenitor addition rate to the expansion of cells from anterior to posterior to simulate vacuolation rate. Comparing this with empirical measurements, we find that progenitor incorporation, together with vacuolation, produces a linear gradient in nearest neighbour distance. We next explored the role of YAP/TAZ in regulating progenitor addition in mutants for the YAP/TAZ inhibitor vgll4b. We find that vgll4b expression and YAP activity are enriched in posterior midline progenitors. Loss of vgll4b elevates YAP signalling, enhances progenitor addition, restricts vacuole expansion, and - after a transient buffering phase - compromises anterior-posterior axis elongation. These results support a long-range feedback mechanism linking progenitor recruitment to vacuolation, enabling the notochord to balance cellular input with volumetric expansion, thereby maintaining tissue proportions.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42596839 · DOI · PMC13615686
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Structure and function of the notochord: an essential organ for chordate development [5]
- Research article The notochordal cell in the nucleus pulposus: a review in the context of tissue engineering [6]
- Research article Notochordal cells in the adult intervertebral disc: new perspective on an old question [7]
- Research article Toward an understanding of the role of notochordal cells in the adult intervertebral disc: from discord to accord [8]
- Research article Morphogenesis of the node and notochord: the cellular basis for the establishment and maintenance of left-right asymmetry in the mouse [9]
- Research article The role of the notochord and floor plate in inductive interactions [10]
References
- Romero MMG, McCathie G, Jankun P, Roehl HH. Damage-induced reactive oxygen species enable zebrafish tail regeneration by repositioning of Hedgehog expressing cells. . 2018. PMID 30275454 · DOI · PMC6167316
- Lleras Forero L, Narayanan R, Huitema LF, VanBergen M, Apschner A, Peterson-Maduro J, et al.. Segmentation of the zebrafish axial skeleton relies on notochord sheath cells and not on the segmentation clock. . 2018. PMID 29624170 · DOI · PMC5962341
- Rohani N, Parmeggiani A, Winklbauer R, Fagotto F. Variable combinations of specific ephrin ligand/Eph receptor pairs control embryonic tissue separation. . 2014. PMID 25247423 · DOI · PMC4172438
- Camacho-Macorra C, Ceccarelli AS, Serrano Nájera G, Saunders D, Boesgaard I, Chara O, et al.. Coupling Vgll4b/Yap-regulated posterior cell addition with anterior vacuolation enables robust notochord elongation. . 2026. PMID 42596839 · DOI · PMC13615686
- Stemple DL. Structure and function of the notochord: an essential organ for chordate development. Development. 2005. PMID 15890825 · DOI
- Hunter CJ, Matyas JR, Duncan NA. The notochordal cell in the nucleus pulposus: a review in the context of tissue engineering. Tissue Eng. 2003. PMID 13678445 · DOI
- Risbud MV, Shapiro IM. Notochordal cells in the adult intervertebral disc: new perspective on an old question. Crit Rev Eukaryot Gene Expr. 2011. PMID 21967331 · DOI · PMC3187872
- Risbud MV, Schaer TP, Shapiro IM. Toward an understanding of the role of notochordal cells in the adult intervertebral disc: from discord to accord. Dev Dyn. 2010. PMID 20568241 · DOI · PMC3634351
- Lee JD, Anderson KV. Morphogenesis of the node and notochord: the cellular basis for the establishment and maintenance of left-right asymmetry in the mouse. Dev Dyn. 2008. PMID 18629866 · DOI · PMC2593123
- Placzek M. The role of the notochord and floor plate in inductive interactions. Curr Opin Genet Dev. 1995. PMID 7580143 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.