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 micromol kg(-1) h(-1)) or NaHCO(3) (981+/-235 micromol 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 approximately 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.
Tresguerres
Martin
M
Department of Biological Sciences, University of Alberta, Edmonton, Alberta T5G 2E9, Canada. martint@ualberta.ca
Katoh
Fumi
F
Fenton
Heather
H
Jasinska
Edyta
E
Goss
Greg G
GG
D000136:Acid-Base Equilibrium / Q000187:drug effects*; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D002245:Carbon Dioxide / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005880:Gills / Q000378:metabolism / Q000502:physiology*; D006400:Hematocrit; D006851:Hydrochloric Acid / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry; D009994:Osmolar Concentration; D017693:Sodium Bicarbonate / Q000494:pharmacology; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D048251:Squalus acanthias / Q000378:metabolism / Q000502:physiology*; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism*
D017923:Sodium-Hydrogen Exchangers; D002245:Carbon Dioxide; D017693:Sodium Bicarbonate; D025262:Vacuolar Proton-Translocating ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D006851:Hydrochloric Acid