TABLE II.
Activation of Ca2+ Current
| Current density at −110 mV in 2 mM Ca2+ |
Activation delay, td | Activation half-time, t1/2 | Number of cells in which current was detected |
|
|---|---|---|---|---|
| pA/pF | s | s | ||
| Passive store depletion | 3.3 ± 0.3 | 75 ± 6 | 50 ± 3 | 63 of 68 |
| Ca2+-buffered control | 0.14 ± 0.04 | >600 | >600 | 2 of 11 |
| 5 μM IP3 | 2.1 ± 0.8 | 60 ± 28 | 60 ± 27 | 5 of 9 |
| 10 μM IP3 | 2.0 ± 0.5 | 107 ± 36 | 97 ± 40 | 5 of 13 |
| 1 μM thapsigargin | 1.9 ± 0.6 | 105 ± 41 | 99 ± 23 | 4 of 4 |
| 10 μM ionomycin | 1.8 ± 0.4 | 20 ± 2 | 21 ± 1 | 4 of 4 |
Current density values are tabulated for cells that had detectable CRAC current. The limit of detection was ∼0.5 pA.