Table 1.
Average muscle dimensions, twitch kinetics, twitch force, and [Ca2+]o responsiveness.
| WT (n=7) | HM (n=8) | |
|---|---|---|
| Length (mm) | 2.9 ± 0.3 | 2.6 ± 0.1 |
| Width (μm) | 329 ± 61 | 333 ± 55 |
| Thickness (μm) | 147 ± 36 | 101 ± 9 |
| Activation time (ms) | 86 ± 4 | 74 ± 4 |
| Relaxation time (ms) | 139 ± 9 | 80 ± 5* |
| Twitch duration (ms) | 225 ± 11 | 154 ± 7* |
| Fmax (mN/mm2) | 92.7 ± 7.3 | 44.1 ± 5.5* |
| Passive Diastolic Stress (mN/mm2) | 3.68 ± 0.45 | 0.67 ± 0.08* |
| EC50 (mM) | 0.42 ± 0.06 | 0.51 ± 0.05 |
| Hill coefficient | 2.5 ± 0.1 | 2.4 ± 0.2 |
Data were collected from electrically stimulated right ventricular cardiac trabeculae isolated from wild-type littermate (WT) or giant titin homozygous mutant (HM) rats. Systolic SL=2.2 μm; stimulus frequency=1 Hz; temperature 25 °C.
*
p<0.05.