XB-IMG-120463
Xenbase Image ID: 120463
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Figure 8. Voltage dependence of DHP block. The currents were
first elicited by voltage pulses to +50 mV followed by voltage steps
to â20 to +90 mV in 10 mV increments. (A) The ShBÎ6-46 T449V
channels do not show significant relaxation after the voltage
change. (B) Slow relaxations of the macroscopic currents through
the ShBÎ6-46 T449V channels in presence of 25 μM nimodipine.
The currents relaxed to lower values at voltages more negative
than +50 mV showing more effective block of nimodipine at these
voltages. (C) Same as B in presence of 100 μM nifedipine. (D)
Voltage-dependent relaxation of the ShBÎ6-46 T449V:A463I current with 100 μM nifedipine. (E) Voltage dependence of the block
for ShBÎ6-46 T449V in the presence of 25 μM (diamonds) and 50
μM (circles) of nifedipine. Relative block was calculated as a ratio of
the current value immediately after the voltage change over the
current value after relaxation based on the single exponential fit of
the current decline. The data sets were fitted with function exp
[nâe (V â 50) / k T] to obtain number of equivalent charges n. (Fâ)
Concentration dependence of the equivalent charges associated
with the voltage dependence of the block obtained as described in
E for nifedipine block of the ShBÎ6-46 T449V current (circles),
ShBÎ6-46 T449V:A463I current (squares), and nimodipine block of
ShBÎ6-46 T449V current (triangles). Solid lines represent the
scheme SV predictions of nifedipine (upper line) and nimodipine
(lower line) block equivalent charges. The model predictions were
calculated using the blocking rate constants obtained from the
concentration dependence data shown in Fig. 4. Data points represent mean ± standard deviation of five to eight experiments. Image published in: Avdonin V et al. (1997) Image reproduced on Xenbase with permission of the publisher and the copyright holder. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |