Table II.
Pharmacological properties of homomeric and heteromeric Kv1 channels
| IC50 values (± SEM) | |||||||||
| Blockers | Adjacent Kv1.1-1.1-1.2-1.2 | Reverse adjacent Kv1.2-1.2-1.1-1.1 | Diagonal Kv1.1-1.2-1.1-1.2 | Reverse diagonal Kv1.2-1.1-1.2-1.1 | Dimer Kv1.1-1.2 | Kv1.1 | Concatenated Kv(1.1)4 | Kv1.2 | Concatenated 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.