Regulation of branchial V-H+-ATPase, Na+/K+-ATPase and NHE2 in response to acid and base infusions in the Pacific spiny dogfish (Squalus acanthias)
To study the mechanisms of branchial acid-base regulation, Pacific spiny dogfish were infused intravenously for 24 h with either HCl (495± 79 μmol kg-1 h-1) or NaHCO 3 (981±235 μmol kg-1 h-1). Infusion of HCl produced a transient reduction in blood pH. Despite continued infusion of acid, pH returned...
| Published in: | Journal of Experimental Biology |
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| Main Authors: | , , , , |
| Format: | Text |
| Language: | English |
| Published: |
Company of Biologists
2005
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| Subjects: | |
| Online Access: | http://jeb.biologists.org/cgi/content/short/208/2/345 https://doi.org/10.1242/jeb.01382 |
| Summary: | To study the mechanisms of branchial acid-base regulation, Pacific spiny dogfish were infused intravenously for 24 h with either HCl (495± 79 μmol kg-1 h-1) or NaHCO 3 (981±235 μmol kg-1 h-1). Infusion of HCl produced a transient reduction in blood pH. Despite continued infusion of acid, pH returned to normal by 12 h. Infusion of NaHCO 3 resulted in a new steady-state acid-base status at ∼0.3 pH units higher than the controls. Immunostained serial sections of gill revealed the presence of separate vacuolar proton ATPase (V-H+-ATPase)-rich or sodium-potassium ATPase (Na+/K+-ATPase)-rich cells in all fish examined. A minority of the cells also labeled positive for both transporters. Gill cell membranes prepared from NaHCO 3 -infused fish showed significant increases in both V-H+-ATPase abundance (300±81%) and activity. In addition, we found that V-H+-ATPase subcellular localization was mainly cytoplasmic in control and HCl-infused fish, while NaHCO 3 -infused fish demonstrated a distinctly basolateral staining pattern. Western analysis in gill membranes from HCl-infused fish also revealed increased abundance of Na+/H+ exchanger 2 (213±5%) and Na+/K+-ATPase (315±88%) compared to the control. |
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