Deactivation (2 msec pulse) | Percentage of τ1 | τ1 (msec) | Percentage of τ2 | τ2 (msec) | Percentage of τ3 | τ3 (msec) | τw (msec) | n |
α1β2 | 53 ± 3 | 9.1 ± 0.5 | 35 ± 3 | 54 ± 5 | 12 ± 1 | 283 ± 28 | 53 ± 3 | 22 |
α1β2(R207C) | 89 ± 2** | 2.8 ± 0.3** | 12 ± 3** | 45 ± 12 | n/a | n/a | 4.9 ± 0.5** | 15 |
Desensitization (1 sec pulse) | Percentage of τ1 | τ1 (msec) | Percentage of τ2 | τ2 (msec) | Extent (%) | τw (msec) | n | |
α1β2 | 46 ± 3 | 15 ± 2 | 27 ± 3 | 630 ± 90 | 27 ± 3 | 260 ± 50 | 10 | |
α1β2(R207C) | 52 ± 2 | 15 ± 1 | 25 ± 3 | 480 ± 70 | 24 ± 2 | 160 ± 25 | 14 | |
Paired pulse recovery | Percentage of τ1 | τ1 (msec) | Percentage of τ2 | τ2 (msec) | Intercept (%) | τw (msec) | n | |
α1β2 | 43 ± 3 | 133 ± 25 | 13 ± 5 | 3564 ± 545 | 43 ± 6 | 700 ± 78 | 7 | |
α1β2(R207C) | 25 ± 4* | 43 ± 24** | 6 ± 2 | 1486 ± 662* | 69 ± 3** | 147 ± 32** | 5 |
All data are given as mean ± SEM. Significant differences between wild-type and mutant parameters were calculated using Student's t test (*p < 0.05; **p < 0.01). τw is the weighted time constant computed as Σai·τi/Σai where ai and τi are the amplitude and time constant of component i. Multi-exponential curve fits were performed with Axograph (deactivation and desensitization) or Prism (paired-pulse recovery).