Table 2.
Estimation of SR Ca2+ release elicited by an action potential in intact EDL fibres (16°C)
| Peak release flux | FDHM of release flux | Δ[CaTotal] | |
|---|---|---|---|
| (μm ms−1) | (ms) | (μm) | |
| A. Normal fibres | 211 | 1.57 | 359 |
| B. mdx fibres | |||
| 1. With standard model parameters | 156 (0.74) | 1.93 (1.23) | 328 (0.91) |
| 2. With [Ca2+]R increased 100% | 157 (0.74) | 1.81 (1.15) | 311 (0.87) |
| 3. With [ParvT] reduced 40% | 158 (0.75) | 1.75 (1.11) | 299 (0.83) |
| 4. With [Ca2+]R increased 100% and[ParvT] reduced 40% | 158 (0.75) | 1.67 (1.06) | 288 (0.80) |
Entries were obtained from simulations with the multi-compartment model described in Methods (cf. Figs 2 and 3); all concentrations are referred to the myoplasmic water volume. Results for normal fibres and for case 1 of mdx fibres used the standard parameter values of the model (Baylor & Hollingworth, 2007). Case 2 of mdx fibres used [Ca2+]R= 100 (rather than 50) nm, case 3 used [ParvT]= 900 (rather than 1500) μm, and case 4 used [Ca2+]R= 100 nm and [ParvT]= 900 μm. In all simulations, the amplitude and FDHM of the release flux were adjusted so that the amplitude and FDHM of the simulated Δ[Ca2+] matched the values in rows 3 and 4 of Table 1 (normal and mdx, respectively). In B, the numbers in parentheses give the ratio of the mdx value to the corresponding normal value.