Closed times for wild-type concatemeric γβα-βα receptors
Receptors were activated by 20-5000 μM GABA. The intracluster closed-time histograms were fitted to sums of three (50-200 μM GABA) or four exponentials. At 20 μM GABA, no clusters were evident. For analysis sections of data containing no overlapping currents were selected. The table gives the mean durations (CT1-4) and prevalence (fraction CT1-4) for the closed-time components. CTβ signifies the GABA concentration-dependent closed time component that arises from dwells in the di-, mono-, and unliganded closed states. The data are presented as mean ± S.D. The number of patches for each condition is given in Table 1.
[GABA] | CT1 | Fraction CT1 | CT2 | Fraction CT2 | CTβ | Fraction CTβ | CT4 | Fraction CT4 |
|---|---|---|---|---|---|---|---|---|
| ms | ms | ms | ms | |||||
| 20 μM | 0.13 ± 0.02 | 0.57 ± 0.12 | 1.0 ± 0.2 | 0.12 ± 0.08 | 94 ± 52 | 0.31 ± 0.05 | ||
| 50 μM | 0.13 ± 0.01 | 0.55 ± 0.05 | 3.6 ± 4.3 | 0.14 ± 0.09 | 34 ± 8 | 0.31 ± 0.08 | ||
| 100 μM | 0.15 ± 0.02 | 0.53 ± 0.05 | 0.9 ± 0.2 | 0.14 ± 0.03 | 15 ± 8 | 0.33 ± 0.05 | ||
| 200 μM | 0.14 ± 0.01 | 0.48 ± 0.11 | 1.6 ± 0.6 | 0.22 ± 0.06 | 9.4 ± 1.5 | 0.30 ± 0.10 | ||
| 500 μM | 0.12 ± 0.00 | 0.52 ± 0.03 | 0.7 ± 0.1 | 0.20 ± 0.05 | 2.4 ± 0.6 | 0.27 ± 0.05 | 9.1 ± 1.1 | 0.02 ± 0.01 |
| 1000 μM | 0.14 ± 0.02 | 0.49 ± 0.03 | 2.9 ± 1.6 | 0.06 ± 0.04 | 0.6 ± 0.1 | 0.44 ± 0.03 | 28 ± 9 | 0.003 ± 0.001 |
| 2000 μM | 0.14 ± 0.03 | 0.53 ± 0.10 | 2.3 ± 0.4 | 0.09 ± 0.10 | 0.5 ± 0.1 | 0.37 ± 0.03 | 19 ± 8 | 0.01 ± 0.01 |
| 5000 μM | 0.16 ± 0.01 | 0.50 ± 0.10 | 1.8 ± 0.3 | 0.09 ± 0.10 | 0.5 ± 0.1 | 0.43 ± 0.09 | 27 ± 6 | 0.003 ± 0.001 |