Mechanisms of acid-base and ionoregulation in white suckers (Catostomus commersoni) in natural soft water - I. Acute exposure to low ambient pH

Helve Hõbe, Chris M. Wood, Brian R. McMahon

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Simultaneous measurements of whole body proton flux and both unidirectional and net ion fluxes together with assessment of the blood acid-base, respiratory gas, electrolyte and lactate status were performed in white suckers (Catostomus commersoni) originating from a natural soft water lake ([Ca++]=0.18 meq·l-1) in Ontario, Canada. Fish were examined under control (pH∼ 6.8) and acidic conditions (pH∼4.3) in natural soft water at 19-20 °C. Resting blood composition was similar to that previously reported for this species in natural hard water except for a marked enhancement of both plasma pH and bicarbonate levels. Acute acid exposure promoted a significant net influx of protons (or loss of base) concomitant with a plasma acidosis of mixed origin (metabolic+respiratory) as well as whole body Na+, Cl-, Ca++ and K+ losses. Circulating ion levels in plasma were partially conserved by intracellular ion depletion. Radiotracer studies showed that net body losses of Na+ and Cl- ensued largely through stimulation of efflux components and, to a lesser extent, inhibition of inward transport. Cl- loss eventually exceeded Na+, suggesting transport of an unmeasured substance to maintain electroneutrality. A markedly reduced blood {Mathematical expression}, enhanced plasma {Mathematical expression}, elevated blood lactate levels and significant hemoconcentration were also observed. Thus, disturbances in acid-base regulation, ionoregulation and respiratory function may all contribute to acid toxicity in white suckers in natural soft water.

Original languageEnglish (US)
Pages (from-to)35-46
Number of pages12
JournalJournal of Comparative Physiology B
Volume154
Issue number1
DOIs
StatePublished - Jan 1 1984

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Biochemistry
  • Physiology
  • Animal Science and Zoology
  • Endocrinology

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