Table 2.
Summary of effects of ICA on the voltage dependence of activation and inactivation for hERG1 monomers (WT) and tetramers containing zero to four F557L (FL) subunits
| Channel type | Control | 30 µM ICA | n | ||
| V0.5 | z | V0.5 | z | ||
| mV | mV | ||||
| V0.5act | |||||
| WT4 | −30.2 ± 1.0 | 3.76 ± 0.22 | NDa | NDa | 12 |
| FL1/WT3 | −25.0 ± 0.6 | 3.76 ± 0.17 | −34.5 ± 1.5 | 4.06 ± 0.39 | 5 |
| WT3/FL1 | −26.9 ± 0.9 | 3.32 ± 0.05 | −36.7 ± 1.1 | 3.57 ± 0.39 | 4 |
| FL1/WT1/FL1/WT1 | −22.7 ± 1.1 | 2.60 ± 0.05 | −29.6 ± 1.6 | 3.00 ± 0.25 | 4 |
| FL2/WT2 | −26.0 ± 1.7 | 3.04 ± 0.15 | −37.1 ± 0.4 | 3.88 ± 0.48 | 4 |
| FL1/WT1/FL2 | −22.0 ± 2.7 | 3.36 ± 0.18 | −19.5 ± 2.9 | 2.80 ± 0.22 | 4 |
| FL4 | −16.4 ± 3.3 | 3.11 ± 0.15 | −18.7 ± 1.0 | 3.60 ± 0.15 | 3 |
| V0.5inact | |||||
| WT4 | −54.4 ± 2.6 | 1.06 ± 0.03 | 57.8 ± 4.1 | 1.17 ± 0.05 | 5 |
| FL1/WT3 | −45.8 ± 3.0 | 1.00 ± 0.04 | 28.5 ± 6.0 | 0.95 ± 0.13 | 4 |
| WT3/FL1 | −57.8 ± 4.4 | 0.90 ± 0.03 | 49.9 ± 4.0 | 1.21 ± 0.03 | 4 |
| FL1/WT1/FL1/WT1 | −51.1 ± 14.3 | 0.80 ± 0.05 | −33.7 ± 16.0 | 0.56 ± 0.03 | 4 |
| FL2/WT2 | −62.7 ± 3.0 | 0.75 ± 0.05 | −22.4 ± 9.3 | 0.46 ± 0.01 | 3 |
| FL1/WT1/FL2 | −79.0 ± 7.8 | 0.67 ± 0.03 | −72.5 ± 7.7 | 0.61 ± 0.05 | 4 |
| FL4 | −103.7 ± 2.4 | 0.65 ± 0.05 | −98.8 ± 7.8 | 0.69 ± 0.04 | 3 |
Data are expressed as mean ± SEM (n = number of oocytes).
a
Not able to measure accurately because tail currents were affected by extracellular K+ accumulation associated with very large outward currents.