Table 1 Description and initial ranges for the varied Niederer-model parameters
Parameter | Description | Minimum value | Maximum value | Default value |
|---|---|---|---|---|
Ca 50ref | Calcium sensitivity at resting sarcomere length (mM) | 0.3e-3 | 0.8e-3 | 0.3e-3 |
k refoff | Unbinding rate of Ca from TnC in the absence of tension (ms-1) | 0 | 0.80 | 0.2 |
k on | Binding rate of Ca to TnC (μM-1 s-1) | 0 | 400 | 100 |
n r | Relaxation parameter | 2 | 4 | 3 |
β 0 | Magnitude of length-dependent activation effects | 1 | 5 | 4.9 |
β 1 | Magnitude of filament overlap effects | -8 | 0 | -4 |
γ | Effect of tension on the unbinding rate of Ca from TnC | 2 | 100 | 2 |
nH | Hill coefficient in the steady-state force-pCa curve | 4 | 9 | 5 |
T ref | Reference tension (kPa) | 100 | 140 | 100 |
α 0 | Monoexponential activation rate seen in caged Ca experiments (ms-1) | 0 | 0.048 | 0.008 |
α r1 | Slow relaxation rate (ms-1) | 0 | 0.012 | 0.002 |
α r2 | Fast relaxation rate (ms-1) | 0 | 0.0105 | 0.00175 |
K z | Relaxation parameter | 0.1 | 0.2 | 0.15 |