碩士 / 國立中興大學 / 生命科學系所 / 101 / To maintain homeostasis, marine teleosts drink seawater (SW) to supplement the internal water and excreted ions from gill, kidney and intestine. In esophagi of the eel (Anguilla japonica) and flounder (Pseudopleuronectes americanus), the epithelial cell exhibited desalination. In the present study, try to examine the osmoregulatory function of esophagus from marco to micro level in the milkfish (Chanos chanos). First, the internal morphologies indicated that there were many spiral valves in the anterior esophagus with deep color; while colorless posterior esophagus showed longitudinal wrinkles. These structures of esophagus are rarely described in other fishes. Histochemistry staining of esophageal sections revealed that no significant changes in epithelial cells between the freshwater (FW) and SW groups. Furthermore, the muscular layer of FW group is thicker than SW group. Our results indicated that posterior esophagus of SW group was dyed by methylene blue. The drinking experiment was designed to investigate the concept that SW-acclimated milkfish drank SW. On the other hand, the system of isolated milkfish esophagus were measured esophageal ion permeability in vitro. The ion permeabilities in the SW groups were more than FW groups. Difference of esophageal permeability implied that there were ion channels involved in the ion transport. Ouabain-inhibitor was performed to determine the effects of NKA whether on the ion permeability in the esophagi of the SW fish. The permeability of esophagus in ouabain group was lower than control group (ouabain-free). Therefore, the NKA expression of anterior esophagus is the SW fish was higher than that of the FW group including gene level, protein level, NKA activity and NKA immunoreactive cell (NKA-IR) number. However, there was no significant difference in the posterior esophagus. In the present study, two kind of Cl- channels are identified in the anterior esophagus with salinity dependent. Expression of CLC-5-like protein in the SW fish was higher than in the FW group, expression of NKCC2-like protein in the FW group was higher than the SW group. Both of the ion transporters to the epithelial cells of spiral valves in the anterior esophagus. Taken together, esophagus was an osmoregulatory organ involved in ion regulation for homeostasis in euryhaline fish milkfish.
| Identifer | oai:union.ndltd.org:TW/101NCHU5105075 |
| Date | January 2013 |
| Creators | Chien-Hung Chen, 陳建宏 |
| Contributors | 李宗翰 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 69 |
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