Characterization of developmental Na(+) uptake in rainbow trout larvae supports a significant role for Nhe3b
| Autor: | Greg G. Goss, Danuta Chamot, David Boyle, Salvatore D. Blair |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
030110 physiology
0301 basic medicine Fish Proteins animal structures Sodium-Hydrogen Exchangers Physiology Sodium chemistry.chemical_element Acid–base homeostasis Biology Biochemistry 03 medical and health sciences Animal science medicine Animals Channel blocker 14. Life underwater Molecular Biology Ion Transport Ecology Hard water Gene Expression Regulation Developmental 6. Clean water Amiloride 030104 developmental biology chemistry Larva Oncorhynchus mykiss Soft water Rainbow trout Homeostasis medicine.drug |
| Zdroj: | Comparative biochemistry and physiology. Part A, Molecularintegrative physiology. 201 |
| ISSN: | 1531-4332 |
| Popis: | Developing freshwater fish must compensate for the loss of ions, including sodium (Na + ), to the environment. In this study, we used a radiotracer flux approach and pharmacological inhibitors to investigate the role of sodium/hydrogen exchange proteins (Nhe) in Na + uptake in rainbow trout ( Oncorhynchus mykiss ) reared from fertilization in soft water (0.1 mM Na + ). For comparison, a second group of embryos/larvae reared in hard water (2.2 mM Na + , higher pH and [Ca 2 + ]) were also included in the experiment but were fluxed in soft water, only. Unidirectional rates of Na + uptake increased throughout development and were significantly higher in embryos/larvae reared in soft water. However, the mechanisms of Na + uptake in both groups of larvae were not significantly different, either in larvae immediately post-hatch or later in development: the broad spectrum Na + channel blocker amiloride inhibited 85–90% of uptake and the Nhe-inhibitor EIPA also caused near maximal inhibitions of Na + uptake. These data indicated Na + uptake was Nhe-mediated in soft water. A role of Nhe3b (but not Nhe2 or Nhe3a) in Na + uptake in soft water was also supported through gene expression analyses: expression of nhe3b increased throughout development in whole embryos/larvae in both groups and was significantly higher in those reared in soft water. This pattern of expression correlated well with measurements of Na + uptake. Together these data indicate that in part, rainbow trout embryos/larvae reared in low Na + soft water maintained Na + homeostasis by an EIPA sensitive component of Na + uptake, and support a primary role for Nhe3b. |
| Databáze: | OpenAIRE |
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