TABLE IV.
Comparison of Larger Measured and Simulated Sparks (Model 1 and Modifications to Model 1)
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|
| Parameters and units | Measurements | 50 nM [Ca2+]R
3.3 pA × 5.3 ms |
100 nM [Ca2+]R
6.0 pA × 5.3 ms |
No Ca2+ pump 3.0 pA × 5.3 ms |
No ATP 2.2 pA × 5.3 ms |
Simplified fluo-3 1.7 pA × 5.3 ms |
| Distance (D) (μm) | 0. 362 ± 0.003 | 0.378 ± 0.003 | 0.361 ± 0.003 | 0.329 ± 0.002 | 0.300 ± 0.002 | |
| 0–100% risetime (ms) | 4.176 ± 0.034 (4.55) |
4.202 ± 0.023 (4.66) |
4.215 ± 0.023 (4.66) |
4.165 ± 0.023 (4.66) |
4.148 ± 0.023 (4.67) |
4.294 ± 0.024 (4.58) |
| Peak amplitude (ΔF/F) | 1.082 ± 0.007 (0.97) |
1.087 ± 0.006 (1.09) |
1.084 ± 0.006 (1.09) |
1.076 ± 0.005 (1.07) |
1.088 ± 0.006 (1.12) |
1.098 ± 0.005 (1.17) |
| Decay time constant (ms) | 4.601 ± 0.044 (5.19) |
7.988 ± 0.063 (7.58) |
8.249 ± 0.063 (7.82) |
7.568 ± 0.063 (7.26) |
6.825 ± 0.058 (6.50) |
10.394 ± 0.065 (9.44) |
| FDHM (ms) | 5.923 ± 0.037 (6.56) |
9.199 ± 0.059 (8.57) |
9.540 ± 0.063 (8.75) |
8.734 ± 0.057 (8.32) |
8.119 ± 0.052 (7.78) |
11.631 ± 0.071 (9.85) |
| Late offset (ΔF/F) | 0.0125 ± 0.0010 (0.014) |
0.0598 ± 0.0007 (0.067) |
0.0626 ± 0.0007 (0.069) |
0.0562 ± 0.0007 (0.063) |
0.0606 ± 0.0007 (0.069) |
0.0626 ± 0.0007 (0.070) |
| FWHM (μm) | 1.019 ± 0.007 (0.96) |
0.873 ± 0.004 (0.84) |
0.916 ± 0.004 (0.88) |
0.881 ± 0.004 (0.85) |
0.779 ± 0.004 (0.75) |
0.707 ± 0.003 (0.69) |
| Mass (μm3) | 1.938 ± 0.047 (1.03) |
0.989 ± 0.017 (0.78) |
1.133 ± 0.019 (0.89) |
1.016 ± 0.019 (0.79) |
0.728 ± 0.019 (0.58) |
0.520 ± 0.010 (0.46) |
| Amplitude at 28–48 ms (ΔF/F) | (0.018) | (0.107) | (0.111) | (0.099) | (0.099) | (0.132) |
Nonparenthesized entries (column 2, measured sparks; columns 3–7, simulated sparks) are the mean ± SEM values of the parameters associated with fits to 3,176 individual sparks (amplitude ΔF/F ≥ 0.7), as illustrated in Fig. 3, C–F. In row 1, D denotes the distance between the scan line and the source, which is known in the simulations (
). All simulated sparks were calculated with the Model 1 troponin reaction (Fig. 1 E) and, except for column 4, with [Ca2+]R = 50 nM. In columns 4–7, the column heading denotes a single modification of the simulation conditions used for column 3 (see text). Parenthesized entries were obtained from fits to the temporal and spatial waveforms of averaged sparks, as illustrated in Fig. 4. All averaged sparks were formed from 1,767 individual sparks aligned at time-of-peak and center location (see Hollingworth et al., 2001); amplitude at 28–48 ms after peak was obtained from Gaussian fits of the type illustrated in Fig. 4, C and F.