QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

Help viewing high resolution images Return to article

Fig. 5. The effect of pre-incubating intestinal cells with epithelial Na⁺ channel (ENaC) inhibitors on rate of Cu accumulation at external [Cu] (Cu_o) ranging from 0–800 µmol l^–1. Cells were pre-incubated for 15 minwithout Cu_o (no added Cu) but with either 100 µmol l^–1 phenamil (open squares), 10 µmol l^–1 CDPC (open diamonds), or 2 mmol l^–1 amiloride (open triangles), compared to controls with no added drug (normal NaCl and no inhibitors, filled triangles) and cells incubated at 4°C without inhibitors (open circles). Drugs were then washed off and cells exposed to 0–800 µmol l^–1 Cu_o for 15 min. All experiments used normal Na⁺_o (140 mmol l^–1 NaCl) throughout. Rapid Cu accumulation in/on cells at time 0 was not deducted from the data. Values are means ± S.E.M. of N=5–6 separate experiments using fresh cells from different individual fish. Different letters (a, b, c or d) indicate a statistically significant difference between adjacent treatments within Cu_o concentration (looking up at adjacent data points between plots at each Cu_o, Kruskal–Wallis test, P<0.05). ¹Significant effect of phenamil compared to amiloride within Cu_o (Kruskal–Wallis test, P<0.05). For clarity, statistical differences between treatment effects (between plots) for 10, 50 and 100 µmol l^–1 Cu_o, respectively, are shown on the insert with the axis expanded for the lowest Cu_o concentrations. The insert also shows the Cu-free (+1 µmol l^–1 EDTA) control (EDTA on the axis label) compared to no added Cu (zero on the axis label). No statistical differences were observed between EDTA and controls with no added Cu (Student's t-tests between EDTA and no added Cu within drug treatment, P>0.05). Cu accumulation rates within drug treatments were all significantly different from the no added Cu control at Cu_o=50 µmol l^–1 or greater (labels not added for clarity; Kruskal–Wallis test, P<0.05). Cu_o effect within ice-cold treatment was significantly different from no added Cu ice control at Cu_o=800 µmol l^–1 only (Kruskal–Wallis test, P=0.0035).

Return to article