Table 2.

Relative contribution of rapid or instantaneous Cu accumulation in/on cells at time zero compared to net Cu accumulation over 15 min exposure to 800μ mol l-1 Cu

Copper accumulation rate (nmol mg-1 cell protein h-1)
TreatmentTime 0 controlAfter 15 minInstantaneous Cu accumulation (%)
Normal Na+0.24±0.14a1.88±0.52*,a12.8
Low Na+0.51±0.05b3.04±0.69*,b16.8
Ice4.63±0.89c,d9.53±4.78c48.5
Amiloride (2 mmol l-1)3.00±0.38c,d21.76±5.15*,d13.8
CDPC (10μ mol l-1)6.39±2.01c39.42±16.56*,d,g,e16.2
Phenamil (100 μmol l-1)6.33±1.36c75.39±13.47*,e8.4
Low Cl-2.58±0.47d21.56±2.44*,d12.0
DIDS (100 μmol l-1)2.79±0.33d18.40±0.94*,f15.1
pH 5.58.84±2.41e32.65±3.70*,g27.1
  • Values are means ± s.e.m, N=5–6 experiments.

    Time 0 control; cells were pipetted into saline containing 800 μmol l-1 Cu and then immediately washed in 0.1 μmol l-1 EDTA solution.

    After 15 min, Cu accumulation rate of cells at the end of a 15 min exposure to saline containing 800 μmol l-1 Cu.

    % instantaneous Cu accumulation=time 0 control/after 15 min × 100%

  • * Significantly different from time 0 control (within rows) by Student's t-test or Mann–Whitney U-test (P<0.05); values within columns with one or more common superscript letters are not significantly different from each other (Kruskal–Wallis test, P>0.05)

  • Cells were pre-incubated with the appropriate epithelial Na+ channel inhibitor for 15 min prior to the addition of Cu