Table 3.
Properties of SR Ca2+ release in response to a single action potential
| 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|
| 16°C | 28°C | |||
| Slow-twitch | Fast-twitch | Slow-twitch | Fast-twitch | |
| (n = 5) | (n = 11) | (n = 1) | (n = 4) | |
| Δ[Ca2+] | ||||
| Peak amplitude (μM) | 127 ± 7 | 346 ± 6* | 120 | 358 ± 9 |
| (d/dt)Δ[CaT] | ||||
| Peak amplitude (μM ms−1) | 70 ± 6 | 212 ± 4* | 105 | 473 ± 28 |
| Time to half-rise (ms) | 2.8 ± 0.2 | 2.6 ± 0.1 | 1.8 | 1.2 ± 0.1 |
| Time to peak (ms) | 3.5 ± 0.2 | 3.3 ± 0.1 | 2.3 | 1.6 ± 0.1 |
| Half-duration (ms) | 1.8 ± 0.1 | 1.6 ± 0.0* | 1.2 | 0.8 ± 0.0 |
Release parameters were estimated from the single-compartment model, as described in the text. Values of time to half-rise and time to peak are relative to the time of the external shock. Asterisks in column 3 denote significant differences between the means in columns 2 and 3 (P < 0.05).