Table 2.
Calcium dependence of nAChR desensitization
| Subtype | τslow(sec) | τfast (sec) | Fast component (%) | Fraction of cells with fast component | ||||
|---|---|---|---|---|---|---|---|---|
| +Ca | −Ca | +Ca | −Ca | +Ca | −Ca2-a | +Ca | −Ca | |
| α4β4 | 129.8 ± 20.2 | 123.7 ± 9.9 | 3.2 ± 1.1 | N/A | 13.6 ± 9.2 | N/A | 2 /5 | 0 /5 |
| α4β2 | 90.7 ± 5.9 | 102.5 ± 20.0 | 5.4 ± 1.5 | 7.4 ± 1.4 | 40.3* ± 3.2 | 11.3 ± 6.1 | 3 /3 | 2 /3 |
| α3β42-b | 204.6 ± 25.4 | 147.4 ± 14.1 | 3.7* ± 0.7 | 11.3 ± 0.9 | 21.8 ± 3.7 | 18.5 ± 3.5 | 6 /11 | 2 /11 |
| α3β2 | 279.6 ± 224.5 | 66.8 ± 16.2 | 8.0 ± 1.5 | 11.3 ± 1.7 | 46.3* ± 8.6 | 66.8 ± 1.0 | 4 /4 | 4 /4 |
All data were obtained from oocytes that were measured in both calcium-free (−Ca) and calcium-containing (+Ca) media.
F2-a
The mean percentage of fast component includes only those oocytes that had a measurable fast component.
F2-b
In some oocytes the two desensitization components were fit separately (see Fig. 2).
*
Indicates significance (p < 0.05), as compared with data obtained in calcium-free media.