Table 1.
Comparison of response properties of rods with normal and reduced GRK1 and arrestin1 concentrations
| Strain | Single-photon response amplitude (pA) | Integration time (ms) | CVarea | t peak,σ2/t peak,μ |
|---|---|---|---|---|
| Isolated single-photon responses | ||||
| Wild type (n = 29) | 1.41 ± 0.09 | 510 ± 20 | 0.34 ± 0.01 | 2.00 ± 0.20 |
| GRK1 +/− (n = 30) | 1.61 ± 0.06 | 840 ± 30 | 0.40 ± 0.02 | 2.90 ± 0.13 |
| GRK1 +/− Arr1 +/− (n = 40), | 1.45 ± 0.05 | 630 ± 20 | 0.43 ± 0.01 | 2.60 ± 0.09 |
| Arr1 +/− (n = 41) | 1.30 ± 0.03 | 500 ± 20 | 0.43 ± 0.02 | 1.88 ± 0.08 |
| Dim flashes, 30°C | ||||
| Wild type (n = 38) | 1.02 ± 0.03 | 490 ± 20 | ||
| GRK1 +/− (n = 43) | 1.30 ± 0.04 | 800 ± 20 | ||
| GRK1 +/− Arr1 +/− (n = 39), | 1.11 ± 0.05 | 610 ± 20 | ||
| Arr1 +/− (n = 36) | 0.76 ± 0.03 | 455 ± 15 | ||
| Dim flashes, 36°C | ||||
| Wild type (n = 15) | 0.98 ± 0.02 | 330 ± 20 | ||
| Arr1 +/− (n = 18) | 0.64 ± 0.01 | 275 ± 20 |
For dim flashes, the amplitude of the mean population single-photon response was determined by dividing the mean response by the number of photoisomerizations, determined by scale factor required to match the time-dependent variance with the square of the mean response. Integration time is the integral of the response normalized by its peak amplitude. CVarea is the SD of the integral of the single-photon response (corrected for dark noise) divided by the mean. t peak,σ2 /t peak,μ is the time-to-peak of the time-dependent variance divided by the time-to-peak of the mean single-photon response. Each entry represents the mean ± SEM. CVarea and t peak,σ2 /t eak,μ can only be reliably estimated for isolated single-photon responses.