Table 1. Ex vivo ERG parameters.
I1/2, photons (505 nm) per flash/µm2 from fitting Equation 1 to photoreceptor (pharmacologically isolated) and bipolar cell (subtracted) amplitude data; Rmax, maximum amplitude measured at plateau of the photoreceptor response and at the peak of the bipolar cell component in response to bright flash (~15,000 photons µm−2); RPR,1/2, photoreceptor response amplitude required for half-maximal bipolar cell response as determined by fitting Equation 2 to RPR – RBC amplitude data. C57 background: Control, one mo, n = 4; P23H, one mo, n = 4; three mo, n = 3; five mo, n = 4 mice/retinas; Gnat2-/- background: Pooled control, 1–6 mo, n = 7 (11); P23H, one mo, n = 4 (6); five mo, n = 11(18); six mo, n = 2 (4) mice(retinas). *p<0.05, **p<0.005, ***p<0.001 in comparison to control data, two-tailed t-test. All data mean ± SEM.
| Photoreceptors | Bipolar cells | ||||
|---|---|---|---|---|---|
| Genotype/age | I1/2 (hn/µm2) | Rmax (µV) | I1/2 (hn/µm2) | Rmax (µV) | RPR,1/2 (µV) |
| 1 month Control P23H/C57 | 74 ± 18 | 410 ± 20 | 24 ± 8 | 1,120 ± 203 | 76 ± 9 |
| 1 month P23H/C57 | 78 ± 10 | 242 ± 29** | 15 ± 2 | 1,152 ± 40 | 29 ± 6** |
| 3 month P23H/C57 | 98 ± 13 | 138 ± 24*** | 71 ± 30 | 547 ± 74* | 39 ± 1* |
| 5 month P23H/C57 | 285 ± 83* | 81 ± 7*** | 72 ± 7* | 388 ± 14* | 24 ± 1** |
| Pooled Control P23H/Gnat2 | 104 ± 17 | 545 ± 76 | 33 ± 12 | 830 ± 160 | 68 ± 9 |
| 1 month P23H/Gnat2 | 230 ± 40** | 238 ± 37** | 48 ± 6 | 670 ± 80 | 38 ± 6* |
| 5 month P23H/Gnat2 | 214 ± 32* | 176 ± 21*** | 42 ± 5 | 540 ± 50 | 28 ± 4*** |
| 6 month P23H/Gnat2 | 339 ± 47*** | 54 ± 8*** | 88 ± 9** | 220 ± 20** | 13 ± 2*** |