TABLE 1.
Alterations of the mid-voltage of activation (V½) derived from conductance-voltage (G-V) curves of DmNav1/TipE, rNav1.2/hβ 1 and rNav1.4/hβ1 expressed in Xenopus oocytes and induced by PbTx-2 and the ΔΔβ-toxins The data represent the mean ± S.E. of at least six independent experiments. The oocytes were clamped at –100 mV and then 50-ms depolarization pulses from –90 to +50 mV were applied at 5-mV increments. The V½, was calculated as described under “Experimental Procedures.”
|
DmNav1/TipE |
rNav1.2/hβ1 |
rNav1.4/hβ1 |
||||
|---|---|---|---|---|---|---|
| μm | V½, mV | μm | V½, mV | μm | V½, mV | |
| Control | –15.9 ± 0.2 | –24.9 ± 0.3 | –24.9 ± 0.2 | |||
| PbTx-2 | 0.5 | –27.7 ± 0.3 | 1 | –33.4 ± 0.6 | 2 | –32.6 ± 0.5 |
| ΔΔBj-xtrIT | 20 | –17.0 ± 0.8 | 20 | –25.1 ± 0.4 | 20 | –25.0 ± 0.5 |
| ΔΔCss4 | 20 | –16.4 ± 0.2 | 20 | –24.9 ± 0.4 | 20 | –24.7 ± 0.4 |
| ΔΔBj-xtrIT + PbTx-2a | 1 + 2 | –16.4 ± 0.3 | 1 + 3 | –25.1 ± 0.3 | 2 + 5 | –25.1 ± 0.2 |
| ΔΔCss4+ PbTx-2a | 1 + 2 | –16.5 ± 0.3 | 1 + 3 | –25.0 ± 0.3 | 2 + 5 | –25.0 ± 0.2 |
a
The ΔΔβ-toxin was applied together with PbTx-2