Effect of Acclimation Time on Nitrite Movement Across the Gill Epithelia of Rainbow Trout: The Role of “Chloride Cells”

Plasma nitrite concentration and the number of lamellar chloride cells were directly correlated in rainbow trout (Salmo gairdneri) transferred from isotonic seawater to fresh water, during a 96-h acclimation period. After a 48-h acclimation, plasma nitrite levels offish exposed to 175 mg/ L of nitrite for 2.5 h were significantly higher than those offish acclimated for 24 h. There was a 9.5-fold increase in the number of lamellar chloride cells during this period. These results suggest that nitrite may be transported across gill epithelia by means of the branchial anion exchange mechanism attributed to lamellar chloride cells in fresh water.