Table 1.

Parameters from exponential fits to deactivation and desensitization and paired pulse recovery

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·τiai 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).