Table 2.
Effects of ωCgtx GVIA, ωAga IVA, nifedipine and ryanodine on gK,Ca1 in the presence of 9AC
| Single action potential | Action potential train | |||
|---|---|---|---|---|
| Current peak (nA) | Total charge(pC) | Current peak(nA) | Total charge(pC) | |
| 9AC (n = 5) | 0.32 ± 0.06 | 41.9 ± 12.4 | 0.72 ± 0.08 | 190 ± 31 |
| 9AC +ωCgtx GVIA | 0.14 ± 0.03 ** | 12.1 ± 4.2 * | 0.46 ± 0.08 * | 111 ± 31 ** |
| 9AC (n = 5) | 0.47 ± 0.06 | 75.5 ± 16.7 | 0.80 ± 0.08 | 329 ± 48 |
| 9AC +ωAga IVA | 0.46 ± 0.05 | 74.0 ± 11.4 | 0.90 ± 0.08 | 371 ± 36 |
| 9AC (n = 11) | 0.44 ± 0.03 | 62.2 ± 4.8 | 0.87 ± 0.05 | 290 ± 24 |
| 9AC + nifedipine | 0.41 ± 0.03 | 50.0 ± 5.3 * | 0.94 ± 0.07 | 277 ± 21 |
| 9AC (n = 7) | 0.39 ± 0.03 | 82.7 ± 17.7 | 0.66 ± 0.07 | 352 ± 64 |
| 9AC + ryanodine | 0.33 ± 0.03 | 60.6 ± 8.0 | 0.63 ± 0.09 | 298 ± 47 |
Tail currents after a single action potential or after a train of six action potentils at 40 Hz were recorded in voltage clamp at a holding potential of −55 mV. Outward Ca2+activated K+ currents were isolated by blocking gCl,Ca with 2 nm. Changes after adding nifedipine (10 μm), ωCgtx GVIA (300 nm), ωAga IVA (40 nm) or ryanodine (20 μm) were compared using Student's paired t test
*
P < 0.05
**
P < 0.01.