Neural fold and neural crest movement in the Mexican salamander Ambystoma mexicanum. 1985

R B Brun

In studies of amphibian neurulation, the terms "neural ridge," "neural fold," and "neural crest" are sometimes used as synonyms. This has occasionally led to the misconception that grafting of the neural crest is equivalent to grafting of the neural fold. The neural fold, however, is composed of three parts: the neural crest, prospective neural tube tissue, and epidermis. In order to investigate how these neural fold components move during neurulation, time-lapse photography, electron microscopy, and grafting were performed. Ambystoma mexicanum embryos were photographed during neurulation at regular intervals. The photographs were analyzed to find the position of those cells at beginning of neurulation that end up on the line of fusion as the neural folds close. Posteriorly, these cells are already on the emerging neural fold. In the anterior neural folds, however, these cells are located in the lateral epidermis. Electron microscopy of the neural folds confirms the presence of epidermis. To follow the movement of the cells differentiating into melanophores (neural crest), neural fold parts were grafted into albino hosts. The crest cells differentiating into melanophores following ectopic grafting are located in the flank of the neural fold that is in contact with the neural plate. In grafts from the outside (distal) flank, no melanophores developed. Semithin sections show that the third part of the neural fold consists of apically constricted cells known to differentiate into neural tissue. Because the neural folds consist of epidermis, neural tissue, and neural crest, neural fold and neural crest cannot be used as synonyms.

UI MeSH Term Description Entries
D008547 Melanophores Chromatophores (large pigment cells of fish, amphibia, reptiles and many invertebrates) which contain melanin. Short term color changes are brought about by an active redistribution of the melanophores pigment containing organelles (MELANOSOMES). Mammals do not have melanophores; however they have retained smaller pigment cells known as MELANOCYTES. Melanophore
D009420 Nervous System The entire nerve apparatus, composed of a central part, the brain and spinal cord, and a peripheral part, the cranial and spinal nerves, autonomic ganglia, and plexuses. (Stedman, 26th ed) Nervous Systems,System, Nervous,Systems, Nervous
D009432 Neural Crest The two longitudinal ridges along the PRIMITIVE STREAK appearing near the end of GASTRULATION during development of nervous system (NEURULATION). The ridges are formed by folding of NEURAL PLATE. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the NEURAL TUBE. Neural Crest Cells,Neural Fold,Neural Groove,Cell, Neural Crest,Cells, Neural Crest,Crest, Neural,Crests, Neural,Fold, Neural,Folds, Neural,Groove, Neural,Grooves, Neural,Neural Crest Cell,Neural Crests,Neural Folds,Neural Grooves
D002465 Cell Movement The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell. Cell Migration,Locomotion, Cell,Migration, Cell,Motility, Cell,Movement, Cell,Cell Locomotion,Cell Motility,Cell Movements,Movements, Cell
D000557 Ambystoma A genus of the Ambystomatidae family. The best known species are the axolotl AMBYSTOMA MEXICANUM and the closely related tiger salamander Ambystoma tigrinum. They may retain gills and remain aquatic without developing all of the adult characteristics. However, under proper changes in the environment they metamorphose. Amblystoma,Ambystoma tigrinum,Tiger Salamander,Amblystomas,Ambystomas,Salamander, Tiger,Salamanders, Tiger,Tiger Salamanders
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia

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