V-H+-ATPase translocation during blood alkalosis in dogfish gills: Interaction with carbonic anhydrase and involvement in the postfeeding alkaline tide

Martin Tresguerres, Scott K. Parks, Chris M. Wood, Greg G. Goss

Research output: Contribution to journalArticle

57 Scopus citations

Abstract

We investigated the involvement of carbonic anhydrase (CA) in mediating V-H+-ATPase translocation into the basolateral membrane in gills of alkalotic Squalus acanthias. Immunolabeling revealed that CA is localized in the same cells as V-H+-ATPase. Blood plasma from dogfish injected with acetazolamide [30 mg/kg at time (t) = 0 and 6 h] and infused with NaHCO 3 for 12 h (1,000 μeq·kg-1·h -1) had significantly higher plasma HCO3- concentration than fish that were infused with NaHCO3 alone (28.72 ± 0.41 vs. 6.57 ± 2.47 mmol/l, n = 3), whereas blood pH was similar in both treatments (8.03 ± 0.11 vs. 8.04 ± 0.11 pH units at t = 12 h). CA inhibition impaired V-H+-ATPase translocation into the basolateral membrane, as estimated from immunolabeled gill sections and Western blotting on gill cell membranes (0.24 ± 0.08 vs. 1.00 ± 0.28 arbitrary units, n = 3; P <- 0.05). We investigated V-H +-ATPase translocation during a postfeeding alkalosis ("alkaline tide"). Gill samples were taken 24-26 h after dogfish were fed to satiety in a natural-like feeding regime. Immunolabeled gill sections revealed that V-H+-ATPase translocated to the basolateral membrane in the postfed fish. Confirming this result, V-H+-ATPase abundance was twofold higher in gill cell membranes of the postfed fish than in fasted fish (n = 4-5; P < 0.05). These results indicate that 1) intracellular H+ or HCO3- produced by CA (and not blood pH or HCO 3-) is likely the stimulus that triggers the V-H +-ATPase translocation into the basolateral membrane in alkalotic fish and 2) V-H+-ATPase translocation is important for enhanced HCO3- secretion during a naturally occurring postfeeding alkalosis.

Original languageEnglish (US)
Pages (from-to)R2012-R2019
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume292
Issue number5
DOIs
StatePublished - May 1 2007

Keywords

  • Acetazolamide
  • Acidbase regulation
  • Bicarbonate secretion
  • Feeding
  • Ion transport
  • Proton reabsorption
  • Squalus acanthias

ASJC Scopus subject areas

  • Physiology

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