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Fig. 5. Dose-dependence of cuticular short-circuit current
(Isc) and transcuticular conductance
(Gcut) inhibition by amiloride. A clamp voltage of 10 mV
with reference to the apical side was maintained to force transcuticular
NH4+ fluxes. In four experiments on different isolated
cuticles, amiloride was added at increasing concentrations to the external
solution. (A) Mean Isc plotted against the concentration
of amiloride (in mol l-1) in the external saline. (B) The
Isc data are shown in a Hanes-Woolf plot. The mean values
of
Imax (maximum short-circuit current) and
Kami (inhibition constant for amiloride) were obtained
from plots for the individual experiments. (C) Mean Gcut
plotted against the concentration of amiloride (in mol l-1) in the
external saline. (D) The Gcut data are shown in a
Hanes-Woolf plot. The mean values of
Gmax (maximum
transcuticular conductance) and KAmi were obtained from
plots for the individual experiments. Values are means ± S.E.M.