Table II.

Pharmacological properties of homomeric and heteromeric Kv1 channels

IC50 values (± SEM)
BlockersAdjacent Kv1.1-1.1-1.2-1.2Reverse adjacent Kv1.2-1.2-1.1-1.1Diagonal Kv1.1-1.2-1.1-1.2Reverse diagonal Kv1.2-1.1-1.2-1.1Dimer Kv1.1-1.2Kv1.1Concatenated Kv(1.1)4Kv1.2Concatenated Kv(1.2)4
TEA (mM)10 ± 0.2 (5)8 ± 1 (4)0.9 ± 0.1 (8)0.8 ± 0.1 (5)9 ± 1 (8)0.47 ± 0.1 (7)0.67 ± 0.1 (4)51 ± 5 (4)47 ± 6 (3)
AgTX1 (nM)15 ± 2 (5) [3.5 ± 0.1 (3)]17 ± 2 (3)9 ± 2 (2)12 ± 1 (11) [4.5 ± 0.1 (3)]20 ± 2 (8)>100 (3)>100 (3)35 ± 4 (3)26 ± 9 (2)
TsTx-Kα (nM)15 ± 2 (4) [1.1 ± 0.05(3)]12 ± 1 (6)14 ± 0.2 (2)17 ± 4 (9) [0.5 ± 0.2 (3)]11 ± 1 (7)>100 (3)>100 (3)3.1 ± 0.5 (5)2.6 ± 0.2 (3)
KTX (nM)4.4 ± 0.5 (5) [6.3 ± 0.1 (3)]6.4 ± 1 (4)11 ± 3 (2)7 ± 1 (3) [2.3 ± 0.04 (3)]6 ± 2 (6)53 ± 9 (2)36 ± 1 (2)>100 (3)>100 (2)
  • Values (mean ± SEM) for activation and inactivation were derived by fitting to single- and double-exponential functions, respectively. V1/2 and slope k were calculated from Boltzmann equation fitting of the gk-V plots. IC50 values are from Hill equation fitting of Ik inhibition by TEA, AgTX1, TsTX-Kα, or KTX. Numbers in square brackets represent Ki values from competition binding experiments (in nM; see Fig. 2 D). n values in round brackets represent the number of experiments.