Table 1.
Effects of temperature and extracellular K+ on Nav1.4 WT and M1476I currents
| Recovery from inactivation | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Activation | Inactivation | τ (ms) with 500 ms conditioning pulse | |||||||||
| [K+]o | V1/2 (mV) | Kv (mV) | V1/2 (mV) | Kv (mV) | τ (ms) with 40 ms conditioning pulse | τ/τfast (ms) | τslow (ms) | % of τfast | % of τslow | ||
| 10°C | 2 mm | M1476I | −40.3 ± 1.9 (n = 10) | −6.6 ± 0.4 (n = 10) | −85.6 ± 1.6† (n = 9) | 5.1 ± 0.2 (n = 9) | 2.16 ± 0.4† (n = 10) | 2.18 ± 0.2 (n = 9) | |||
| WT | −40.2 ± 1.8 (n = 8) | −6.2 ± 0.5 (n = 8) | −91.5 ± 1.4 (n = 8) | 4.8 ± 0.1 (n = 8) | 3.8 ± 0.2 (n = 8) | 4.2 ± 0.4 (n = 6) | 139 ± 30 (n = 6) | 95 ± 0.6 (n = 6) | 4.7 ± 0.7 (n = 6) | ||
| 18°C | 2 mm | M1476I | −40.9 ± 1.1 (n = 12) | −5.7 ± 0.3 (n = 12) | −79.6 ± 0.9† (n = 12) | 4.7 ± 0.1* (n = 12) | 0.78 ± 0.04† (n = 12) | 0.9 ± 0.05 (n = 12) | |||
| WT | −39.3 ± 1.0 (n = 9) | −5.8 ± 0.4 (n = 9) | −84.1 ± 0.7 (n = 9) | 4.4 ± 0.1 (n = 9) | 1.8 ± 0.1 (n = 8) | 2.0 ± 0.1 (n = 7) | 111.5 ± 17.3 (n = 7) | 93.4 ± 1.1 (n = 7) | 8.1 ± 0.3 (n = 7) | ||
| 23°C | 2 mm | M1476I | −41.7 ± 1.2 (n = 35) | −5.2 ± 0.1 (n = 35) | −74.2 ± 0.5† (n = 35) | 4.5 ± 0.04† (n = 35) | 0.51 ± 0.03† (n = 27) | 0.65 ± 0.03† (n = 26) | 65.4 ± 3.6 (n = 26) | 90.72 ± 0.5 (n = 26) | 8.8 ± 0.5 (n = 26) |
| WT | −40.3 ± 1.2 (n = 21) | −5.0 ± 0.2 (n = 21) | −80.6 ± 0.5 (n = 21) | 4.2 ± 0.1 (n = 21) | 0.86 ± 0.02 (n = 11) | 1.1 ± 0.1 (n = 11) | 71.7 ± 5.5 (n = 11) | 89.4 ± 0.8 (n = 11) | 10.0 ± 0.6 (n = 11) | ||
| 23°C | 4 mm | M1476I | −42.8 ± 1.4 (n = 7) | −4.7 ± 0.2 (n = 7) | −76.8 ± 1.3† (n = 7) | 4.1 ± 0.1 (n = 7) | 0.54 ± 0.01† (n = 7) | 0.59 ± 0.2† (n = 7) | 76.9 ± 4.8 (n = 7) | 90.8 ± 1.1 (n = 7) | 8.5 ± 1.1 (n = 7) |
| WT | −41.9 ± 1.4 (n = 7) | −5.0 ± 0.7 (n = 7) | −81.5 ± 1.5 (n = 5) | 4.2 ± 0.2 (n = 5) | 0.97 ± 0.03 (n = 5) | 1.1 ± 0.07 (n = 5) | 79.6 ± 4.7 (n = 5) | 87.4 ± 0.6 (n = 5) | 11.7 ± 0.6 (n = 5) | ||
| 23°C | 6 mm | M1476I | −43.6 ± 1.4 (n = 7) | −4.6 ± 0.3 (n = 7) | 77.1 ± 1.0† (n = 7) | 4.1 ± 0.1 (n = 7) | 0.59 ± 0.03† (n = 6) | 0.62 ± 0.04† (n = 6) | 76.1 ± 4.9 (n = 6) | 88.7 ± 1.3 (n = 6) | 10.8 ± 1.1 (n = 6) |
| WT | −42.9 ± 1.0 (n = 6) | −4.8 ± 0.2 (n = 6) | −82.3 ± 1.0 (n = 6) | 4.3 ± 0.2 (n = 6) | 1.2 ± 0.1 (n = 6) | 1.3 ± 0.1 (n = 6) | 79.7 ± 4.3 (n = 6) | 89.3 ± 0.6 (n = 6) | 10.2 ± 0.5 (n = 6) | ||
| 23°C | 9 mm | M1476I | −42.1 ± 1.5 (n = 12) | −4.7 ± 0.3 (n = 12) | −75.6 ± 1.0† (n = 10) | 4.5 ± 0.1 (n = 10) | 0.57 ± 0.03† (n = 7) | 0.68 ± 0.04† (n = 8) | 73.5 ± 5.1 (n = 8) | 87.5 ± 1.2 (n = 8) | 11.6 ± 1.1 (n = 8) |
| WT | −40.3 ± 0.9 (n = 9) | −5.2 ± 0.2 (n = 9) | −82.0 ± 1.6 (n = 9) | 4.3 ± 0.1 (n = 9) | 1.1 ± 0.1 (n = 7) | 1.3 ± 0.1 (n = 7) | 75.9 ± 3.1 (n = 7) | 88.2 ± 1.2 (n = 7) | 11.3 ± 1.2 (n = 7) | ||
*
P < 0.5,
†
P < 0.01, data was significantly different for mutant channels when compared to WT.