Table 4.
Effect of hERG channel blockers on thallium influx in hERG-transduced and KV1.3 cells
| Compound | hERG | KV 1.3 | Selectivity | ||
|---|---|---|---|---|---|
| IC50 | Efficacy | IC50 | Efficacy | Fold | |
| 1,3-diphenylguanidine | 6.9 ± 3 | 39 ± 12 | Inactive | ||
| benzethonium chloride | 3.6 ± 1.4 | 77 ± 9 | 18±6 | 93 ± 20 | 5 |
| domiphen bromide | 4.3 ± 1.0 | 62 ± 11 | 5.2 ± 0.6 | 102 ± 22 | 1.2 |
| econazole nitrate | 7.2 ± 2.8 | 112 ± 11 | 30 ± 2 | 104 ± 10 | 4.2 |
| malachite green oxalate | 4.8 ± 0.8 | 108 ± 7 | 31 | 89 | 6.5 |
| o,p′ –DDT | 22.2 ± 4.1 | 58 ± 8 | 35 | 61 | 1.6 |
| quinidine | 13.6 ± 5.4 | 110 ± 13 | Inactive | ||
| reserpine | 4.9 ± 1.7 | 118 ± 7 | 58 ± 18 | 78 ± 7 | 11.8 |
| tamoxifen, citrate salt | 8.3 ± 0.8 | 110 ± 4 | 22 ± 3 | 108 | 2.7 |
| tetra-n-octylammonium bromide | 0.26 ± 0.1 | 100 ± 3 | 11 ± 8 | 72 ± 16 | 42 |
| tricresyl phosphate | 9.7 ± 1.6 | 68 ± 16 | 26 ± 7 | 68 ± 17 | 2.7 |
| verapamil | 3.4 ± 0.8 | 100 ± 8 | 30 ± 3 | 88 ± 12 | 8.8 |
Abbreviations: DDT = 1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane
Each value of potency (IC50, μM) and efficacy (inhibition of thallium influx as a % of positive control) from thallium influx assays in hERG-transduced and KV1.3 cells is the mean ± SD from two to three experiments.