Table 1.
Summary of exponential fits to deactivation and desensitization
| Deactivation (4 ms pulse) |
% τfast | τfast (ms) | % τslow | τslow (ms) | τw (ms) | n | |
|---|---|---|---|---|---|---|---|
| α1β2γ2 | 76±2 | 7.3±0.8 | 24±2 | 124.5±12.7 | 37.4 ± 5.4 | 14 | |
| α1β2Y97Aγ2 | 84±2 | 5.2±0.8 | 16±2 | 51.3±20.0** | 11.8 ± 2.7 ** | 6 | |
| α1β2Y97Fγ2 | 74±2 | 3.9±0.3* | 26±2 | 45.4±4.7** | 14.7 ± 1.6 ** | 5 | |
| α1β2Y157Aγ2 | 84±8 | 1.8±0.5** | 16±2 | 17.1±5.2** | 3.1 ± 1.1 ** | 4 | |
| α1β2Y157Fγ2 | 73±9 | 4.1±0.7* | 27±2 | 17.5±2.9** | 8.5 ± 2.1 ** | 5 | |
| α1β2Y205Fγ2 | 75±4 | 2.6±0.1** | 25±2 | 15.0±2.8** | 5.2 ± 0.4 ** | 8 | |
| Desensitization (500 ms pulse) |
% τfast | τfast (ms) | % τslow | τslow (ms) | % remaining |
τw (ms) | n |
| α1β2γ2 | 32±3 | 7.4±1.0 | 29±2 | 247.8±12.6 | 39±2 | 130 ± 11 | 39 |
| α1β2Y97Aγ2 | 35±4 | 3.6±1.2 | 32±3 | 272.3±22.4 | 33±8 | 136 ± 20 | 12 |
| α1β2Y97Fγ2 | 56±3** | 4.0±0.5 | 25±2 | 170.0±12.0** | 19±2** | 58 ± 9 ** | 10 |
| α1β2Y157Aγ2 | 10±6* | 2.2±1.1 | 29±2 | 190.1±34.9 | 61±4** | 139 ± 14 | 4 |
| α1β2Y157Fγ2 | 43±2* | 6.0±0.6 | 24±1 | 244.9±10.6 | 33±1 | 96 ± 10 | 17 |
| α1β2Y205Fγ2 | 28±3 | 10.±1.3 | 31±2 | 280.0±22.8 | 41±2 | 160 ± 18 | 11 |
Deactivation and desensitization phases were fit with bi-exponential equations, Y= A1 · e−t/τfast + A2 · e−t/τslow and Y= A1 · e−t/τfast + A2 · e−t/τslow + C, performed with Axograph. The weighted time constant (τw) was computed (A1/(A1 + A2)) · τfast + (A2/(A1+A2)) · τslow. Significant differences between wild-type and mutant receptors were calculated using ANOVA with a Dunnett’s posttest
*
p < 0.05;
**
p < 0.01