Figure 5.
![Figure 5. High-affinity ionic block predicts a reduced current after a 50% increase in blocker concentration The model described by Eq. 5 was used to predict the effect on current amplitude of changing the divalent cation concentration from 4 to 6 mM (as is Fig. 2 B) for different blocking affinities. High-affinity block ([B]/KD ≥ 10) predicts a ∼33% decline in current amplitude, which is inconsistent with the experimental data (see Fig. S1). The lack of a significant change in amplitude in Fig. 2 B would be consistent with a low-affinity block ([B]/KD ≤ 10), but low-affinity block is not sufficient to account for the broad voltage range of current saturation.](https://cdn.rupress.org/rup/content_public/journal/jgp/132/4/10.1085_jgp.200809967/7/jgp_200809967_lw_fig5.jpeg?Expires=1767758777&Signature=UAFSRdag0IYNAozu4oDrdXHs8CoHp4xD43-P0LQdenKBroBayI3g9mwhNi40FGvFwuuI9fRyq6N7ilugj~ryhHHdTNZO7OYqz9til~~JJOlQ7PFcF7evgQQFYA69FMmzQxjvE41i8FRfzhfXvdjJbetx~Z~aSFfRvUbHKsE9Y1xbBau7Y4VzcU9KrxW3ibd1Mc1GUMv2eSl5FqURoTsuiq97dGD8wW~4d8jJXwoz6zG2NeEaS6oBUq5TN7QHqivQBlVTV5naZKeDu2nLWWteB-KiKwwKBY2z1Hz2We~S5DJZTTZE~6YKcyV5gLrSaf1LgBalM3coI5AMQaRAiVp1lw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
High-affinity ionic block predicts a reduced current after a 50% increase in blocker concentration The model described by Eq. 5 was used to predict the effect on current amplitude of changing the divalent cation concentration from 4 to 6 mM (as is Fig. 2 B) for different blocking affinities. High-affinity block ([B]/KD ≥ 10) predicts a ∼33% decline in current amplitude, which is inconsistent with the experimental data (see Fig. S1). The lack of a significant change in amplitude in Fig. 2 B would be consistent with a low-affinity block ([B]/KD ≤ 10), but low-affinity block is not sufficient to account for the broad voltage range of current saturation.
