Time constants for wild-type α1β1γ2s and mutant α1β1γ2s(L287A) receptors
PRO lengthened all three single-channel open-time components in mutant receptors but not in wild-type receptors. Open-time constants are reported as unweighted mean values ± S.E.M. pooled from individual fits of each patch. Values from global fits of pooled data are shown in parentheses and are automatically weighted by the number of events detected for each component. When a component in the individual fit was missing compared with the global fit, the value was ignored and designated N.D. when calculating the mean values. PRO produced significant increases in the open time constants of mutant receptors. To a lesser extent, PRO also decreased the longer of the two closed time components (τC2) in mutant receptors. Under our single-channel recording and analysis conditions, PRO had no effect on wild-type receptors.
| Time Constants | |||||
|---|---|---|---|---|---|
| τC1 | τC2 | τO1 | τO2 | τO3 | |
| ms | |||||
| WT − PRO | 0.41 ± 0.03 | 1.74 ± 0.14 | 0.72 ± 0.06 | 1.95 ± 0.22 | 8.61 ± 1.71 |
| (0.46) | (2.02) | (0.78) | (2.48) | (9.02) | |
| WT + PRO | 0.47 ± 0.08 | 1.73 ± 0.14 | 0.64 ± 0.06 | 1.91 ± 0.14 | 6.10 ± 0.54 |
| (0.41) | (1.81) | (0.69) | (2.18) | (7.12) | |
| MUT − PRO | 0.46 ± 0.05 | 1.91 ± 0.24 | 0.69 ± 0.07 | 2.01 ± 0.14 | N.D. |
| (0.56) | (2.50) | (0.84) | (2.11) | ||
| MUT + PRO | 0.32 ± 0.04 | 1.19 ± 0.20† | 1.14 ± 0.15† | 5.71 ± 0.80† | 24.97 ± 2.63† |
| (0.30) | (1.27) | (0.78) | (4.94) | (25.44) | |
N.D., not determined.
* P < 0.05 vs. WT − PRO.
↵† P < 0.05 vs. MUT − PRO.