Ionoregulatory changes in the gill epithelia of coho salmon during seawater acclimation

Physiol Biochem Zool. May-Jun 2002;75(3):237-49. doi: 10.1086/341817.

Abstract

Short-term exposure of coho salmon smolts (Oncorhynchus kisutch) to a gradual increase in salinity over 2 d (0 per thousand -32 per thousand ) resulted in a decrease in proton pump abundance, detected as changes in immunoreactivity with a polyclonal antibody against subunit A of bovine brain vacuolar H(+)-ATPase. N-ethylmaleimide (NEM)-sensitive H(+)-ATPase activities in gill homogenates remained unchanged over 8 d to coincide with a 3.5-fold increase in Na(+)/K(+)-ATPase activities. A transient increase in plasma [Na(+)] and [Cl(-)] levels over the 8-d period was preceded by a 10-fold increase in plasma cortisol levels, which peaked after 12 h. Long-term (1 mo) acclimation to seawater resulted in the loss of apical immunoreactivity for vH(+)-ATPase and band 3-like anion exchanger in the mitochondria-rich cells identified by high levels of Na(+)/K(+)-ATPase immunoreactivity. The polyclonal antibody Ab597 recognized a Na(+)/H(+) exchanger (NHE-2)-like protein in what appears to be an accessory cell (AC) type. Populations of these ACs were found associated with Na(+)/K(+)-ATPase rich chloride cells in both freshwater- and seawater-acclimated animals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological*
  • Animals
  • Chlorides / metabolism
  • Epithelium / metabolism*
  • Fresh Water
  • Gills / metabolism*
  • Ion Transport
  • Salmon / metabolism*
  • Seawater / chemistry*
  • Sodium / metabolism
  • Sodium-Hydrogen Exchangers / metabolism
  • Sodium-Potassium-Exchanging ATPase / metabolism
  • Time Factors
  • Tissue Distribution
  • Water-Electrolyte Balance

Substances

  • Chlorides
  • Sodium-Hydrogen Exchangers
  • Sodium
  • Sodium-Potassium-Exchanging ATPase