Steady-state and kinetic mechanical parameters measured in skeletal (larvae and adult zebrafish) and cardiac (adult zebrafish and mouse) myofibrils.
| Myofibril type: | Skeletal | Cardiac | ||
| Animal model: | Larvae zebrafish | Adult zebrafish | Adult zebrafish | Adult mouse |
| SL0 (µm) | 2.02 ± 0.02 | 2.03 ± 0.03 | 2.12 ± 0.04 | 2.03 ± 0.03 |
| (n = 12) | (n = 22) | (n = 16) | (n = 7) | |
| Fmax (nN/µm2) | 40.1 ± 4.7 | 18.4 ± 1.5 | 49.8 ± 4.6 | 58.1 ± 4.4 |
| (n = 11)a | (n = 22) | (n = 15) | (n = 7) | |
| pCa50 | ND | 5.14 ± 0.02 | 5.44 ± 0.04 | 5.35 ± 0.06 |
| (n = 5) | (n = 8) | (n = 7) | ||
| nH | ND | 2.38 ± 0.19 | 1.71 ± 0.23 | 1.66 ± 0.31 |
| (n = 5) | (n = 8) | (n = 7) | ||
| Fpass (nN/µm2) | 4.2 ± 0.5 | 2.3 ± 0.2 | 4.0 ± 0.3 | 3.3 ± 0.4 |
| (n = 10)a | (n = 22) | (n = 15) | (n = 7) | |
| kACT (s−1) | 27.0 ± 5.3 | 11.3 ± 1.4 | 5.2 ± 0.6 | 5.6 ± 0.2 |
| (n = 10)b | (n = 15) | (n = 15) | (n = 7) | |
| kLIN (s−1) | 11.6 ± 2.3 | 6.3 ± 0.7 | 1.9 ± 0.2 | 2.2 ± 0.1 |
| (n = 11)c | (n = 10) | (n = 15) | (n = 7) | |
| tLIN (ms) | 16.7 ± 2.9 | 18.8 ± 2.2 | 48.7 ± 2.9 | 34.6 ± 2.2 |
| (n = 11) | (n = 10) | (n = 15)b | (n = 7) | |
| kREL (s−1) | 121.0 ± 22.5 | 77.1 ± 10.9 | 24.9 ± 1.5 | 33.6 ± 2.3 |
| (n = 11) | (n = 10) | (n = 15)b | (n = 7) | |
| τREL−1 (s−1) | 52.7 ± 9.9 | 34.1 ± 4.4 | 11.9 ± 0.6 | 16.2 ± 1.0 |
| (n = 11) | (n = 10) | (n = 15)b | (n = 7) | |
| Myofibril type: | Skeletal | Cardiac | ||
| Animal model: | Larvae zebrafish | Adult zebrafish | Adult zebrafish | Adult mouse |
| SL0 (µm) | 2.02 ± 0.02 | 2.03 ± 0.03 | 2.12 ± 0.04 | 2.03 ± 0.03 |
| (n = 12) | (n = 22) | (n = 16) | (n = 7) | |
| Fmax (nN/µm2) | 40.1 ± 4.7 | 18.4 ± 1.5 | 49.8 ± 4.6 | 58.1 ± 4.4 |
| (n = 11)a | (n = 22) | (n = 15) | (n = 7) | |
| pCa50 | ND | 5.14 ± 0.02 | 5.44 ± 0.04 | 5.35 ± 0.06 |
| (n = 5) | (n = 8) | (n = 7) | ||
| nH | ND | 2.38 ± 0.19 | 1.71 ± 0.23 | 1.66 ± 0.31 |
| (n = 5) | (n = 8) | (n = 7) | ||
| Fpass (nN/µm2) | 4.2 ± 0.5 | 2.3 ± 0.2 | 4.0 ± 0.3 | 3.3 ± 0.4 |
| (n = 10)a | (n = 22) | (n = 15) | (n = 7) | |
| kACT (s−1) | 27.0 ± 5.3 | 11.3 ± 1.4 | 5.2 ± 0.6 | 5.6 ± 0.2 |
| (n = 10)b | (n = 15) | (n = 15) | (n = 7) | |
| kLIN (s−1) | 11.6 ± 2.3 | 6.3 ± 0.7 | 1.9 ± 0.2 | 2.2 ± 0.1 |
| (n = 11)c | (n = 10) | (n = 15) | (n = 7) | |
| tLIN (ms) | 16.7 ± 2.9 | 18.8 ± 2.2 | 48.7 ± 2.9 | 34.6 ± 2.2 |
| (n = 11) | (n = 10) | (n = 15)b | (n = 7) | |
| kREL (s−1) | 121.0 ± 22.5 | 77.1 ± 10.9 | 24.9 ± 1.5 | 33.6 ± 2.3 |
| (n = 11) | (n = 10) | (n = 15)b | (n = 7) | |
| τREL−1 (s−1) | 52.7 ± 9.9 | 34.1 ± 4.4 | 11.9 ± 0.6 | 16.2 ± 1.0 |
| (n = 11) | (n = 10) | (n = 15)b | (n = 7) | |
Where applicable, values were compared between skeletal myofibrils from larvae and from adult zebrafish (second and third columns), and between cardiac myofibrils from adult zebrafish and from mouse (fourth and fifth columns). Maximum generated isometric force (Fmax) was determined at saturating [Ca2+], pCa 4.5; passive force (Fpass) was evaluated in relaxing condition (pCa 7.5) at SL = 1.15 × SL0. Data for murine cardiac myofibrils was taken from (Iorga et al., 2008). ND, not determined.
P < 0.001; unpaired t test.
P < 0.01; unpaired t test.
P < 0.05; unpaired t test.