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. Author manuscript; available in PMC: 2007 Sep 7.
Published in final edited form as: J Membr Biol. 2007 Mar 8;213(1):19–29. doi: 10.1007/s00232-006-0037-y

Figure 3.

Figure 3

Whole-cell characteristics of Kir2.1 and Kir2.4 stably expressed in HEK 293 cells showing differential sensitivity to Ba2+. (A) Effects of increasing concentration of Ba2+ on a family of currents evoked by 600 ms voltage steps from −150 to +20 mV at a holding potential of −20 mV in a 60/140 K+ gradient. (B) Mean I-V relationships of steady-state current plotted relative to control current at −150 mV recorded in the absence (○) and presence (▽) of 100 μM Ba2+ for currents expressed by Kir2.1 (n=6-12) (closed symbols) and Kir2.4 (n=6) (open symbols). (C) Concentration-response curves for the Ba2+-induced block shown for currents recorded at −100 mV. Values for the dissociation constant (KD) and the slope factor (n) were derived by the fit to Eq 1. For Kir 2.1, the KD was 3.9 μM (n=0.85) at −100 mV, and the corresponding value for Kir 2.4 was 65.6 μM (n=0.83)