| Myofibril batch . | Tension generation . | Relaxation in slow or fast phase . | ||||
|---|---|---|---|---|---|---|
| . | P0 . | kACT . | kTR . | Dslow . | Slow kREL . | Fast kREL . |
| . | kN m−2 . | s−1 . | s−1 . | ms . | s−1 . | s−1 . |
| Rabbit fast skeletal | ||||||
| 0 µM MAVA | 612 ± 54 (6) | 7.28 ± 0.51 (6) | 7.61 ± 0.53 (6) | 88 ± 7 (6) | 2.09 ± 0.16 (6) | 41 ± 5.6 (6) |
| 2.5 µM MAVA | 460 ± 51 (4) | 4.13 ± 0.61a (4) | 4.58 ± 0.32a (4) | 76 ± 6 (4) | 1.82 ± 0.25 (4) | 37 ± 3.4 (4) |
| 5 µM MAVA | 415 ± 41b (4) | 2.35 ± 0.08c (4) | 3.02 ± 0.20c (4) | 74 ± 8 (4) | 1.40 ± 0.35 (4) | 30 ± 1.6 (4) |
| 10 µM MAVA | 360 ± 30d (9) | 3.05 ± 0.12c (9) | 3.36 ± 0.27c (9) | 82 ± 6 (9) | 1.54 ± 0.20 (9) | 36 ± 2.6 (9) |
| Human ventricle | ||||||
| 0 µM MAVA | 100 ± 11 (11) | 0.68 ± 0.04 (11) | 0.53 ± 0.02 (11) | 176 ± 16 (9) | 0.40 ± 0.05 (10) | 4.25 ± 0.41 (9) |
| 0.1 µM MAVA | 80 ± 8 (7) | 0.64 ± 0.04 (6) | 0.55 ± 0.03 (7) | 130 ± 10 (6) | 0.37 ± 0.07 (6) | 6.35 ± 0.66b (7) |
| 0.5 µM MAVA | 41 ± 7d (10) | 0.60 ± 0.04 (10) | 0.56 ± 0.04 (10) | 152 ± 17 (10) | 0.77 ± 0.11a (9) | 5.97 ± 0.46b (10) |
| 1 µM MAVA | 17 ± 4d (4) | 0.68 ± 0.02 (4) | 0.75 ± 0.05d (3) | 200 ± 37 (4) | 0.86 ± 0.17a (4) | 4.94 ± 0.53 (4) |
| Myofibril batch . | Tension generation . | Relaxation in slow or fast phase . | ||||
|---|---|---|---|---|---|---|
| . | P0 . | kACT . | kTR . | Dslow . | Slow kREL . | Fast kREL . |
| . | kN m−2 . | s−1 . | s−1 . | ms . | s−1 . | s−1 . |
| Rabbit fast skeletal | ||||||
| 0 µM MAVA | 612 ± 54 (6) | 7.28 ± 0.51 (6) | 7.61 ± 0.53 (6) | 88 ± 7 (6) | 2.09 ± 0.16 (6) | 41 ± 5.6 (6) |
| 2.5 µM MAVA | 460 ± 51 (4) | 4.13 ± 0.61a (4) | 4.58 ± 0.32a (4) | 76 ± 6 (4) | 1.82 ± 0.25 (4) | 37 ± 3.4 (4) |
| 5 µM MAVA | 415 ± 41b (4) | 2.35 ± 0.08c (4) | 3.02 ± 0.20c (4) | 74 ± 8 (4) | 1.40 ± 0.35 (4) | 30 ± 1.6 (4) |
| 10 µM MAVA | 360 ± 30d (9) | 3.05 ± 0.12c (9) | 3.36 ± 0.27c (9) | 82 ± 6 (9) | 1.54 ± 0.20 (9) | 36 ± 2.6 (9) |
| Human ventricle | ||||||
| 0 µM MAVA | 100 ± 11 (11) | 0.68 ± 0.04 (11) | 0.53 ± 0.02 (11) | 176 ± 16 (9) | 0.40 ± 0.05 (10) | 4.25 ± 0.41 (9) |
| 0.1 µM MAVA | 80 ± 8 (7) | 0.64 ± 0.04 (6) | 0.55 ± 0.03 (7) | 130 ± 10 (6) | 0.37 ± 0.07 (6) | 6.35 ± 0.66b (7) |
| 0.5 µM MAVA | 41 ± 7d (10) | 0.60 ± 0.04 (10) | 0.56 ± 0.04 (10) | 152 ± 17 (10) | 0.77 ± 0.11a (9) | 5.97 ± 0.46b (10) |
| 1 µM MAVA | 17 ± 4d (4) | 0.68 ± 0.02 (4) | 0.75 ± 0.05d (3) | 200 ± 37 (4) | 0.86 ± 0.17a (4) | 4.94 ± 0.53 (4) |
Each group of data was collected in different myofibril batches activated and relaxed by fast solution switch. Rabbit fast skeletal and human ventricle myofibrils were treated with different concentrations of MAVA as described. All values are given as mean ± SEM; values in parentheses are the myofibril numbers. Dslow, duration of the slow phase of relaxation.
P < 0.005 versus Ctrl myofibrils (Student’s t test).
P < 0.05 versus Ctrl myofibrils (Student’s t test).
P < 0.0001 versus Ctrl myofibrils (Student’s t test).
P < 0.001 versus Ctrl myofibrils (Student’s t test).