Table III.
Effect of Patch Excison and ATP on Single-Channel Kinetics
| c/a | Control (i/o) | ATP (i/o) | Wash (i/o) | |||||
|---|---|---|---|---|---|---|---|---|
| Kir6.2ΔC26 (n = 3) | ||||||||
| P o | 0.088 ± 0.01 | 0.050 ± 0.01 | 0.063 ± 0.01 | |||||
| τo (ms) | 0.82 ± 0.07 | 0.72 ± 0.06 | 0.78 ± 0.07 | |||||
| τC1 (ms) | 0.30 ± 0.03 | 0.31 ± 0.03 | 0.31 ± 0.03 | |||||
| Kir6.2ΔC26-C166S (n = 3) | ||||||||
| P o | 0.63 ± 0.05 | 0.78 ± 0.05 | 0.49 ± 0.13 | 0.68 ± 0.02 | ||||
| τo (ms) | 1.43 ± 0.1 | 1.47 ± 0.08 | 1.36 ± 0.07 | 1.34 ± 0.02 | ||||
| τC1 (ms) | 0.34 ± 0.04* | 0.28 ± 0.01 | 0.28 ± 0.01 | 0.28 ± 0.01 | ||||
| τC2 (ms) | 21.4 ± 5.5 | 14.2 ± 2.3 | 9.9 ± 2.0 | 18.1 ± 1.4 | ||||
| Percent C2 | 1.06 ± 0.31 | 0.46 ± 0.2 | 4.8 ± 3.7 | 0.90 ± 0.35 | ||||
| τC3 (ms) | 159 ± 39 | |||||||
| Percent C3 | 0.35 ± 0.11 | |||||||
| Burst duration (ms) | 47 ± 9 | 247 ± 56 | 38 ± 9 | 152 ± 63 | ||||
| No. openings/burst | 27 ± 5 | 129 ± 25 | 22 ± 6 | 81 ± 29 |
All parameters were measured at −60 mV. c/a, cell attached; i/o, inside out; Percent C2 and C3, percentage of closed time occupied by C2 and C3. The ATP concentration was 100 μM in the case of wtKir6.2ΔC26 currents and 10 mM for Kir6.2ΔC26-C166S currents.
*
P < 0.05 against the excised patch data (paired t test).