Table 2.

Effects of K+ channel blockers on fast and slowIK(M,ng), Imerg1a, andIK(M)

BlockerSlowIK(M,ng)Imerg1aFastIK(M,ng)IK(M)
WAY 123,398
 IC50m)0.4  ± 0.070.3  ± 0.02no effect (10 μm)no effect (10 μm)
 nH1.0  ± 0.20.9  ± 0.07
(4)(6)(37)(9)
Azimilide
 IC50m)6.5  ± 0.76.4  ± 0.331.1  ± 1.812.9  ± 0.7
 nH0.9  ± 0.080.8  ± 0.030.9  ± 0.051.3  ± 0.09
(5)(4)(4)(3)
THA
 IC50m)11.5  ± 1.535.7  ± 9.71542  ± 2001279  ± 75
 nH0.6  ± 0.050.6  ± 0.10.7  ± 0.070.8  ± 0.03
(3)(7)(3)(4)
Linopirdine
 IC50m)>>30>301.2  ± 0.023.5  ± 0.2
 nH1.2  ± 0.030.8  ± 0.04
(4)(6)(6)(6)
TEA
 IC50 (mm)16.7  ± 3.424.1  ± 3.61.1  ± 0.0910.9  ± 0.7
 nH0.8  ± 0.10.6  ± 0.10.6  ± 0.030.6  ± 0.02
(6)(3)(5)(4)
Ba2+
 IC50m)134  ± 6492  ± 57248  ± 26393  ± 36
 nH1.0  ± 0.041.0  ± 0.10.9  ± 0.070.8  ± 0.05
(3)(5)(3)(3)
  • Mean ± SEM. Number of cells in parentheses. Inhibition constants (IC50) were determined from dose–response curves of the type illustrated in Figures 7 and 9. Effects on fast and slow currents in NG108-15 cells were determined from kinetic analysis of deactivation tails as illustrated in Figure 2, supplemented (where appropriate) by tests after inhibiting the slow component with WAY 123,398, as in Figure 9.