El-Balshy, R., El-Serafy, S., El-Hashash, A. (2002). THE DEVELOPMENT OF THE NEURAL CREST IN THE CEPHALIC REGION OF XIPHOPHORUS HbJ.LRl. Egyptian Journal of Aquatic Biology and Fisheries, 6(3), 85-120. doi: 10.21608/ejabf.2002.1752
Ragaa El-Balshy; Sabry El-Serafy; Ahmed El-Hashash. "THE DEVELOPMENT OF THE NEURAL CREST IN THE CEPHALIC REGION OF XIPHOPHORUS HbJ.LRl". Egyptian Journal of Aquatic Biology and Fisheries, 6, 3, 2002, 85-120. doi: 10.21608/ejabf.2002.1752
El-Balshy, R., El-Serafy, S., El-Hashash, A. (2002). 'THE DEVELOPMENT OF THE NEURAL CREST IN THE CEPHALIC REGION OF XIPHOPHORUS HbJ.LRl', Egyptian Journal of Aquatic Biology and Fisheries, 6(3), pp. 85-120. doi: 10.21608/ejabf.2002.1752
El-Balshy, R., El-Serafy, S., El-Hashash, A. THE DEVELOPMENT OF THE NEURAL CREST IN THE CEPHALIC REGION OF XIPHOPHORUS HbJ.LRl. Egyptian Journal of Aquatic Biology and Fisheries, 2002; 6(3): 85-120. doi: 10.21608/ejabf.2002.1752
THE DEVELOPMENT OF THE NEURAL CREST IN THE CEPHALIC REGION OF XIPHOPHORUS HbJ.LRl
Dept. of Zoology, Faculty of Science, Bertha, Zagazig University, Hgypt
Abstract
The site, time of segregation and migratory pathways of the neural crest cells are studied in the head region of seven developmental stages (0.7; 1.0; 1.5; 2.0; 3.0; 4.2 and 6.0 mm total length) of the teieost fish Xiphophorus helleri Moreover, the changes in the distribution of the extracellular matrix components during the migration of the neural crest cells and their differentiation are also considered. The formation, segregation and migration of the neural crest cell take place after complete formation of the neural keel in an antero-poslerior direction. The migration of the neural crest cells at the head region occurred in three migratory pathways. The first pathway is ventral along the brain and notochord. The second pathway is lateral in the sub-eclodermal space. The third pathway, contralateral pathway, is across the dorsal midline of the fore-brain and mid-brain.Non-sullat.ed giycosamiuoglycans are the main extracellular matrix (UCM) components, that may facilitate the neural crest celt migration and invasion to form the corneal endothelium and some cartilages of the chondrocraniucn. Sulfated glycosaminoglycans may provoke the arrest of the crest cells to form the iris melanophorcs.The cranial neural crest cells are aggregated at certain levels to form the presumptive proximal ganglionic primordia of 5U (Irigeimnal), 7lh (facial) 9lh? (glossophavyngeal). and 10lh (vagus) cranial nerves. Neutral polysaccharides are stm to be the predominant matrix components that probably provoke the crest cell aggregation to form these structures and siromal fibroblasis.
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