| Group . | pCa50 . | nH . | Fmax (mN/mm2) . | Fmin (mN/mm2) . |
|---|---|---|---|---|
| WT | ||||
| Pre-OM | 5.85 ± 0.03 | 2.22 ± 0.09 | 18.13 ± 2.87 | 1.16 ± 0.21 |
| 0.5 µM OM | 6.02 ± 0.01 (*, P = 0.005) | 1.49 ± 0.04 (*, P = 0.0008) | 13.47 ± 3.01 | 1.61 ± 0.31 |
| 1.0 µM OM | 6.08 ± 0.04 (*, P = 0.0002) | 1.03 ± 0.02 (*, P < 0.0001) | 12.26 ± 1.83 | 1.92 ± 0.19 |
| SA | ||||
| Pre-OM | 5.86 ± 0.02 | 2.10 ± 0.12 | 12.95 ± 1.77 | 1.02 ± 0.24 |
| 0.5 µM OM | 5.79 ± 0.03 (&, P = 0.005) | 2.05 ± 0.14 (&, P = 0.01) | 12.21 ± 1.29 | 1.70 ± 0.33 |
| 1.0 µM OM | 5.97 ± 0.02 | 1.33 ± 0.02 (*, P = 0.0005) | 9.10 ± 1.03 | 1.15 ± 0.25 |
| Group . | pCa50 . | nH . | Fmax (mN/mm2) . | Fmin (mN/mm2) . |
|---|---|---|---|---|
| WT | ||||
| Pre-OM | 5.85 ± 0.03 | 2.22 ± 0.09 | 18.13 ± 2.87 | 1.16 ± 0.21 |
| 0.5 µM OM | 6.02 ± 0.01 (*, P = 0.005) | 1.49 ± 0.04 (*, P = 0.0008) | 13.47 ± 3.01 | 1.61 ± 0.31 |
| 1.0 µM OM | 6.08 ± 0.04 (*, P = 0.0002) | 1.03 ± 0.02 (*, P < 0.0001) | 12.26 ± 1.83 | 1.92 ± 0.19 |
| SA | ||||
| Pre-OM | 5.86 ± 0.02 | 2.10 ± 0.12 | 12.95 ± 1.77 | 1.02 ± 0.24 |
| 0.5 µM OM | 5.79 ± 0.03 (&, P = 0.005) | 2.05 ± 0.14 (&, P = 0.01) | 12.21 ± 1.29 | 1.70 ± 0.33 |
| 1.0 µM OM | 5.97 ± 0.02 | 1.33 ± 0.02 (*, P = 0.0005) | 9.10 ± 1.03 | 1.15 ± 0.25 |
pCa50, myofilament Ca2+ sensitivity; nH, cooperativity of force production; Fmax, maximal Ca2+-activated force measured at pCa 4.5; Fmin, Ca2+-independent force measured at pCa 9.0. Values are expressed as mean ± SEM. Data from multiple preparations from each heart were averaged, and 9–13 myocardial preparations from three or four hearts were used per group. *, Significantly different compared with the corresponding pre-OM group. &, Significantly different compared with the corresponding WT group.