Effects of γ2(P302L) subunit mutation on α1β3γ2L receptor single-channel properties
| α1β3γ2L | α1β3γ2L(P302L) | ||
|---|---|---|---|
| Single-channel properties | pa | ||
| Open probability | 0.547 ± 0.036 | 0.217 ± 0.072 | 0.0015 |
| Mean open time, ms | 16.5 ± 6.49 | 6.46 ± 0.93 | 0.1500 |
| Opening Frequency, S−1 | 17.8 ± 0.05 | 4.81 ± 0.86 | 0.0386 |
| Mean closed time, ms | 249 ± 141 | 1718 ± 613 | 0.0287 |
| Open time constants | pb | ||
| τO1, ms | 2.33 ± 0.46 | 2.53 ± 0.06 | 0.0215 |
| τO2, ms | 11.2 ± 1.55 | 3.42 ± 0.29 | |
| τO3, ms | 40.7 ± 8.34 | 20.4 ± 2.04 | |
| aO1, % | 62 ± 10 | 38 ± 7 | 0.0040 |
| aO2, % | 14 ± 4 | 52 ± 5 | |
| aO3, % | 25 ± 11 | 18 ± 3 | |
| Conductance | pb | ||
| Low openings, pS | 15.16 ± 0.59 | 13.41 ± 0.38 | 0.7287 |
| Main openings, pS | 25.34 ± 1.77 | 22.89 ± 0.575 | |
| Low openings, % | 36.57 ± 2.381 | 82.98 ± 6.731 | 0.0001 |
| Main openings, % | 63.43 ± 2.381 | 25.53 ± 6.392 |
Kinetic parameters of single-channel currents in cell-attached patches held at +80 mM with 1 mM GABA in the glass electrodes were obtained. The τs and as refer to the time constants and fractions of the three exponential components (O1, O2, and O3), which best represent the distributions of the single-channel openings. Values refer to combined data of low- and main-conductance openings reported are mean ± SEM (n = 7). aUnpaired two-tailed Student’s t test relative to α1β3γ2L. bTwo-way ANOVA with Sidak’s multiple comparisons test relative to α1β3γ2L.