Table 1. Parameters describing the rod dim flash response in vivo.
| Parameter | Description | Value | |
|---|---|---|---|
| Ex vivoa | In vivo | ||
| kR* | Rate of R* deactivation (s−1) | 25 | — |
| kE | Rate of G*-E* deactivation (s−1) | 5 (WT) or 12.5 (RGS9-ox) | 8 (WT) or 21.7 (RGS9-ox) |
| νRE | Max rate of G*-E* activation per R* (s−1) | 300 | 350 |
| βidvb | Rate of cGMP hydrolysis per G*-E* (s−1) | 43 | — |
| βdark | Rate of spontaneous cGMP hydrolysis (s−1) | 4.1 | — |
| DcGb | Longitudinal diffusion coefficient of cGMP (µm2 s−1) | 40 | — |
| fCab | Fraction of current carried by calcium | 0.12 | — |
| αdarkc | Dark cGMP synthesis rate (µM s−1) | 16.7 | 19.1 |
| Cαdarkb | Dark adapted Ca2+ concentration (nM) | 320 | Set by αdark |
| cGdarkb | Dark adapted cGMP concentration (µM) | 4.1 | Set by αdark and βdark |
| BCab | Calcium buffer capacity | 50 | — |
| ncycb | Hill coefficient for Ca2+ dependence of cGMP synthesis | 1.5 | — |
| Kcycb | K1/2 for Ca2+ dependence of cGMP synthesis (nM) | 80 | — |
| αmax | Max rate of cGMP synthesis (µM s−1) | 150 | 172 |
| Kex | K1/2 for NCKX activation (µM) | 1.1 | — |
| Jexsat | Maximum NCKX current (pA µm−1) | 0.21 | — |
b
Value was held fixed for all simulations.
c
Value was adjusted so that for both ex vivo and in vivo, αdark/αmax = 9.