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Ultrastructural features of the gut in the white sturgeon, Acipenser transmontanus
G. Radaelli1, C. Domeneghini2, S. Arrighi2, M. Francolini3 and F. Mascarello1
1Department of Animal Science, Faculty of Veterinary Medicine, Agripolis, Legnaro, Padua, Italy, 2Institute of Domestic Animals Anatomy, Histology and Embriology, Faculty of Veterinary Medicine, Milan, Italy and 3CNR Cellular and Molecular Pharmacology Center, Milan, Italy
Offprint requests to: Prof. Cinzia Domeneghini, Istituto di Anatomia degli Animali Domestici, Facoltà di Medicina Veterinaria, Via Celoria, 10, I-20133 Milano, Italy. Fax: +39.02.2367788. e-mail: Cinzia.Domeneghini@unimi.it
Summary. Electron-microscopic examinations of the sturgeon gut were performed. Oesophageal goblet cells were abundant in the stratified epithelium. The ultrastructural features of the secretory granules of the oesophageal and intestinal goblet cells were quite similar to those of other vertebrates. Lobules of multilocular adipose tissue were observed in the deep tunica propria-submucosa of the oesophagus, in close association with vasculature and large fibre bundles of myelinated and unmyelinated axons. Similarly composed nerve fibre bundles were observed in the cardiac stomach, too. The presence of myelinated axons is an unusual feature in the vertebrate enteric nervous system. Cardiac and fundic zones of the stomach showed an epithelium with columnar ciliated and non-ciliated cells, the latter equipped with fuzzy microvilli. Cells lining the tubular gastric proper glands were markedly granulated. Intestinal superficial epithelium was columnar and contained ciliated, as well as non-ciliated and goblet cells. In the tunica propria all over the intestine, the presence and ultrastructure of granulated cells was in addition described. Intraepithelial granulated leukocytes were seen throughout the alimentary canal. Various types of endocrine cells were seen both in the stomach and in the intestine, the size of their granules was measured and their ultrastructure described and compared to that of mammalian cell types. Histol. Histopathol. 15, 429-439 (2000)
Key words: Sturgeon,
Gut, Morphology, Ultrastructure, Neuroendocrine system
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