Table 2.
Effect of β1 overexpression on Na+ current characteristics in MDA-MB-231 cells
| Parametera | Control | β1 |
|---|---|---|
| Cm (pF) | 22.4 ± 1.8 | 19.8 ± 0.9 |
| Ip (pA/pF) | -34.5 ± 4.2 | -46.4 ± 4.1 * |
| Iper at -35 mV (pA/pF) | -1.6 ± 0.4 | -2.2 ± 0.3 |
| Va (mV) | -54.0 ± 0.8 | -54.5 ± 0.9 |
| Vp (mV) | -1.0 ± 1.2 | -4.5 ± 1.5 |
| Activation V1/2 (mV) | -21.3 ± 0.9 | -23.3 ± 2.6 |
| Activation k (mV) | 10.2 ± 0.5 | 10.0 ± 0.7 |
| Inactivation V1/2 (mV) | -83.6 ± 0.8 | -84.8 ± 0.6 |
| Inactivation k (mV) | -7.9 ± 0.8 | -6.5 ± 0.3 |
| Tp at 0 mV (ms) | 0.73 ± 0.03 | 0.65 ± 0.02 * |
| τf at 0 mV (ms) | 0.51 ± 0.03 | 0.50 ± 0.03 |
| τs at 0 mV (ms) | 3.7 ± 0.4 | 3.7 ± 0.4 |
a
Abbreviations: Cm, membrane capacitance; Ip, peak current density; Iper, persistent current density; Va, activation voltage; Vp voltage at current peak; V1/2, half (in)activation voltage; k, slope factor; Tp time to peak; τf/s, fast/slow time constant of inactivation.
Data are expressed as mean ± SEM.
*
Significance: P < 0.05 (n = 20).