Table 2.
Dynamic contractile parameters of WT and KO ventricular multicellular preparations.
| Group | ktr (s−1) | krel (s−1) | kdf (s−1) | P1 |
|---|---|---|---|---|
| SL 1.9 μm | ||||
| WT | 8.74 ± 0.56* | 45.01 ± 4.06* | 12.26 ± 1.53* | 0.535 ± 0.022* |
| KO | 8.03 ± 0.54 | 36.96 ± 2.94 | 9.64 ± 0.39 | 0.543 ± 0.048 |
| SL 2.1 μm | ||||
| WT | 5.71 ± 0.40 | 34.21 ± 2.12 | 8.17 ± 0.52 | 0.604 ± 0.016 |
| KO | 8.90 ± 0.37† | 45.76 ± 4.01† | 11.27 ± 0.67† | 0.528 ± 0.026† |
ktr: rate force redevelopment; krel: rate of force decay; kdf: rate of force development; P1: the magnitude of peak force attained following a rapid stretch of muscle length in an isometrically-activated muscle preparation. krel and kdf were estimated using a linear transformation of the half time of force decay and force redevelopment. Values are expressed as mean ± s.e.m., from 6 to 13 multicellular preparations and 3 to 4 hearts per each group.
*
Significantly different from the corresponding WT group at SL 2.1 μm; P < 0.05.
†
Significantly different from the corresponding WT group at SL 2.1 μm, P < 0.05.