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)

• Published in: Journal of Experimental Biology
• Main Authors: Tresguerres, Martin, Katoh, Fumi, Fenton, Heather, Jasinska, Edyta, Goss, Greg G.
• Format: Text
• Language: English
• Published: Company of Biologists 2005
• Subjects: Research Article; Pacific; spiny dogfish; Squalus acanthias
• Online Access: http://jeb.biologists.org/cgi/content/short/208/2/345; https://doi.org/10.1242/jeb.01382

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.