TABLE 2.
Estimated activation and binding parameters and mean IC50 for bupivacaine block of Kv channels
| Channel type | α* (ms−1) | β* (ms−1) | κ (ms−1 mM−1) | λ (ms−1) | Kd (mM) | IC50 (n) (mM) | IC50/Kd |
|---|---|---|---|---|---|---|---|
| Inactivating channels | |||||||
| Shaker | 1.0 | 0 | 1.5 | 0.45 | 0.30 | 1.6 ± 0.1 (9) | 5.3 |
| Kv3.4 | 0.2 | 0 | 0.1 | 0.006 | 0.06 | 1.2 ± 0.06 (10) | 20 |
| Noninactivating channels | |||||||
| Shaker-IR | 0.42 | 0 | 1.2 | 0.34 | 0.28 | 0.24 ± 0.03 (5) | 0.86 |
| Kv1.1 | 0.23 | 0 | 0.5 | 0.10 | 0.20 | 0.24 ± 0.02 (4) | 1.2 |
| Kv1.2 | 0.27 | 0 | 1.2 | 0.22 | 0.18 | 0.21 ± 0.02 (12) | 1.2 |
| Kv1.5 | 0.15 | 0 | 0.8 | 0.10 | 0.12 | 0.13 ± 0.04 (6) | 1.1 |
| Kv3.1 | 0.16 | 0 | 0.5 | 0.06 | 0.12 | 0.13 ± 0.03 (4) | 1.1 |
| Kv3.2 | 0.17 | 0 | 0.5 | 0.04 | 0.09 | 0.11 ± 0.02 (5) | 1.2 |
*
Value at V = +60 mV except for Shaker and Shaker-IR, where V = +20 mV. Values for Kv1.1, 1.2, 1.5, 3.1, and 3.2 from Nilsson et al. (32) included for a comparison.