Table 1.
Effects of extracellular K+ on recovery from inactivation in Kv1.5 and Kv1.5ΔN209
| Full-length Kv1.5 | Kv1.5ΔN209 | |||||||
|---|---|---|---|---|---|---|---|---|
| Inactivation voltage | +10 mV | +60 mV | −20 mV | −60 mV | ||||
| [k+]o | 5 | 135 | 5 | 135 | 5 | 135 | 5 | 135 |
| τfast | 0.15 ± 0.02 | 0.18 ± 0.05 | 0.17 ± 0.03 | 0.13 ± 0.02 | 0.085 ± 0.007* | 0.09 ± 0.02 | 0.10 ± 0.05 | 0.17 ± 0.06 |
| τslow | 2.6 ± 0.2 | 2.0 ± 0.5 | 3.19 ± 0.4 | 3.0 ± 0.5 | 1.14 ± 0.02* | 0.69 ± 0.06* | 1.8 ± 0.3* | 3.6 ± 1.2 |
| Fast component (%) | 17 ± 1 | 22 ± 2 | 15 ± 4 | 15 ± 1 | 25 ± 3* | 33 ± 6 | 5.3 ± 0.9* | 28 ± 11 |
| Slow component (%) | 30 ± 1 | 26 ± 1 | 37 ± 3 | 32 ± 1 | 42 ± 2* | 47 ± 8 | 56 ± 4* | 47 ± 5 |
| Non-inactivated (%) | 53 ± 1 | 53 ± 1 | 49 ± 6 | 54 ± 2 | 32 ± 1* | 20 ± 2* | 39 ± 3 | 24 ± 5* |
| Weight (fast) | 36 ± 1 | 45 ± 2 | 28 ± 2 | 32 ± 3 | 37 ± 4 | 42 ± 7 | 9 ± 2* | 38 ± 14 |
| Weight (slow) | 64 ± 1 | 55 ± 2 | 72 ± 2 | 68 ± 2 | 63 ± 3 | 58 ± 9 | 91 ± 6* | 62 ± 7 |
Recovery from inactivation was examined using the protocol described in Fig. 8, with either 5 mm or 135 mm extracellular K+, and fitted with a bi-exponential equation.
*
Statistical difference between Kv1.5ΔN209 and full-length Kv1.5 in the same condition (P < 0.05). Amplitudes of each component of recovery are listed as the fraction of total current (s labelled fast component and slow component), and as the fraction of inactivated current (s labelled weight (fast) and weight (slow)).