Time constants from exponential fits to dwell time histograms
| Fitted dwell time components (τ) in μs . | CTZ n = 7 . | CII n = 5 . | (R, R)-2b n = 3 . | CII + (R, R)-2b n = 6 . |
|---|---|---|---|---|
| Closed | ||||
| τ1 | 300 ± 90 | 260 ± 50 | 170 ± 20 | 540 ± 210 |
| τ2 | 2,400 ± 1,400 | 1,500 ± 300 | 1,080 ± 70 | 5,800 ± 4,200 (5) |
| A1 | 89 ± 7% | 95 ± 2% | 91 ± 8% | 89 ± 6% |
| Open 1 | ||||
| τ1 | 240 ± 20 | 240 ± 40 | 140 ± 20 | 180 ± 50 |
| τ2 | 600 ± 300 (2) | — | 400 ± 50 | 480 ± 320 (2) |
| A1 | 92 ± 6% | 100% | 95 ± 5% | 93 ± 8% |
| Open 2 | ||||
| τ1 | 280 ± 30 | 200 ± 10 | 220 ± 60 | 230 ± 40 |
| τ2 | 570 (1) | — | — | 400 ± 140 (3) |
| A1 | 97 ± 3% | 100% | 100% | 86 ± 13% |
| Open 3 | ||||
| τ1 | 260 ± 20 | 170 ± 20 | 180 ± 80 | 220 ± 50 |
| τ2 | 700 (1) | 330 ± 30 (3) | 240 (1) | — |
| A1 | 99 ± 1% | 85 ± 14% | 86 ± 17% | 100% |
| Open 4 | ||||
| τ1 | 320 ± 70 | 180 ± 40 | 250 ± 80 | 270 ± 50 (5) |
| τ2 | 1,200 ± 400 (6) | — | 900 ± 300 | 2,500 ± 1,800 (4) |
| A1 | 87 ± 4% | 100% | 75 ± 11% | 98 ± 1% |
| Fitted dwell time components (τ) in μs . | CTZ n = 7 . | CII n = 5 . | (R, R)-2b n = 3 . | CII + (R, R)-2b n = 6 . |
|---|---|---|---|---|
| Closed | ||||
| τ1 | 300 ± 90 | 260 ± 50 | 170 ± 20 | 540 ± 210 |
| τ2 | 2,400 ± 1,400 | 1,500 ± 300 | 1,080 ± 70 | 5,800 ± 4,200 (5) |
| A1 | 89 ± 7% | 95 ± 2% | 91 ± 8% | 89 ± 6% |
| Open 1 | ||||
| τ1 | 240 ± 20 | 240 ± 40 | 140 ± 20 | 180 ± 50 |
| τ2 | 600 ± 300 (2) | — | 400 ± 50 | 480 ± 320 (2) |
| A1 | 92 ± 6% | 100% | 95 ± 5% | 93 ± 8% |
| Open 2 | ||||
| τ1 | 280 ± 30 | 200 ± 10 | 220 ± 60 | 230 ± 40 |
| τ2 | 570 (1) | — | — | 400 ± 140 (3) |
| A1 | 97 ± 3% | 100% | 100% | 86 ± 13% |
| Open 3 | ||||
| τ1 | 260 ± 20 | 170 ± 20 | 180 ± 80 | 220 ± 50 |
| τ2 | 700 (1) | 330 ± 30 (3) | 240 (1) | — |
| A1 | 99 ± 1% | 85 ± 14% | 86 ± 17% | 100% |
| Open 4 | ||||
| τ1 | 320 ± 70 | 180 ± 40 | 250 ± 80 | 270 ± 50 (5) |
| τ2 | 1,200 ± 400 (6) | — | 900 ± 300 | 2,500 ± 1,800 (4) |
| A1 | 87 ± 4% | 100% | 75 ± 11% | 98 ± 1% |
Single-channel recordings of GluA2 wild type receptors were obtained in glutamate (10 mM) and the following positive allosteric modulators: CTZ (100 µM), CII toxin (100–500 nM), (R, R)-2b (10 μM), or CII + (R, R)-2b. Histograms of dwell times of closed and open levels (1–4) were obtained from idealized single-channel traces and fit with one or two exponential components (Fig. 7; τ1 and τ2). The amplitude of the first component (A1) is expressed in percent where appropriate, and n is the number of patches. Where only a subset of patches in the group could be fit, the number of patches in this subset used to obtain the time constant is given in parentheses.