Table 1.
Tension Generation and Relaxation Parameters after Recombinant Rat cTn Containing Either cTnI-WT or cTnI-P83S Exchange into Rat Ventricular Myofibrils at 15°Ca
| relaxation | ||||||
|---|---|---|---|---|---|---|
| tension generation | slow-phase | |||||
| myofibril batches | tension (mN/mm2) | kACT (s−1) | kTR (s−1) | tREL,slow (ms) | kREL,slow (s−1) | fast phase kREL,fast (s−1) |
| pCa = 4.0 | ||||||
| WT | 74.6 ± 5.8 (16) | 3.3 ± 0.3 (16) | 5.3 ± 0.5 (16) | 72 ± 3 (16) | 0.9 ± 0.1 (16) | 17 ± 2 (16) |
| WT+PKA | 71.1 ± 6.5 (17) | 2.5 ± 0.2* (17) | 5.2 ± 0.7 (17) | 63 ± 3* (16) | 1.6 ± 0.2* (16) | 17 ± 2 (16) |
| P83S | 74.5 ± 5.0 (22) | 3.7 ± 0.2*,$ (22) | 6.1 ± 0.5 (22) | 71 ± 2 (22) | 1.0 ± 0.1*,$ (22) | 18 ± 2 (22) |
| P83S+PKA | 70.3 ± 3.9 (23) | 3.5 ± 0.3*,$ (23) | 5.9 ± 0.4 (22) | 74 ± 3*,$ (22) | 1.1 ± 0.2*,$ (22) | 19 ± 2 (22) |
| pCa = 5.4 | ||||||
| WT | 32.7 ± 3.6 (15) | 1.8 ± 0.2 (15) | 3.5 ± 0.4 (15) | 67 ± 4 (15) | 1.6 ± 0.2 (14) | 17 ± 2 (15) |
| WT+PKA | 21.5 ± 2.7* (16) | 1.5 ± 0.2 (16) | 3.1 ± 0.3 (15) | 56 ± 4* (14) | 3.7 ± 0.6* (14) | 18 ± 3 (15) |
| P83S | 35.7 ± 2.9*,$ (16) | 2.1 ± 0.2 (16) | 4.0 ± 0.3 (16) | 67 ± 3*,$ (15) | 1.9 ± 0.3*,$ (15) | 17 ± 2 (16) |
| P83S+PKA | 33.9 ± 2.4*,$ (15) | 2.1 ± 0.2 (15) | 3.8 ± 0.3 (14) | 68 ± 4 (14) | 2.2 ± 0.3 (14) | 18 ± 1 (14) |
a
Values given are mean ± SE. Number in parentheses is number of myofibrils.
*
p < 0.05 vs WT, and
*,$
p < 0.05 vs WT+PKA.