Table 2.
Comparison of twitch and tetanus parameters in fatigued γ+/+ and γ−/− muscles
| At T50% | At T30% | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| EDL (n = 4) | Soleus (n = 3) | EDL (n = 4) | ||||||||||
| γ+/+ | S.E.M. | γ−/− | S.E.M. | γ+/+ | S.E.M. | γ−/− | S.E.M. | γ+/+ | S.E.M. | γ−/− | S.E.M. | |
| Twitch | ||||||||||||
| Tension (mN) | 18.27 | 1.35 | 15.64 | 1.22 | 5.58 | 1.32 | 8.47 | 0.59 | 13.44 | 1.07 | 10.73 | 0.93 |
| tpeak (ms) | 19.80 | 0.50 | 18.20 | 0.98 | 29.33 | 2.36 | 37.73 | 3.67 | 18.40 | 0.65 | 17.55 | 0.57 |
| t1/2 (ms) | 25.10 | 1.97 | 25.20 | 2.56 | 65.46 | 8.08 | 91.33 | 1.93 | 25.30 | 1.98 | 24.70 | 2.30 |
| Tetanus | ||||||||||||
| Tension (mN) | 105.91 | 4.21 | 90.71 | 9.87 | 35.55 | 4.45 | 34.07 | 3.15 | 63.29 | 2.41 | 58.84 | 4.53 |
| t1/2, contract (ms) | 45.50 | 1.55 | 42.75 | 2.25 | 118.00 | 3.06 | 126.00 | 2.31 | 39.75 | 0.85 | 38.50 | 1.66 |
| t1/2,relax (ms) | 92.00 | 1.22 | 85.5 | 3.66 | 133.67 | 9.17 | 147.67 | 2.96 | 87.00 | 2.12 | 79.75 | 4.27 |
| Twitch/tetanus | 0.170 | 0.008 | 0.168 | 0.007 | 0.133 | 0.041 | 0.165 | 0.047 | 0.195 | 0.015 | 0.189 | 0.012 |
For each genotype four experiments were carried out on EDL and three experiments on soleus muscle. Values were determined when the tetanus amplitude had declined to 50% of its initial value (T50%) in EDL and soleus and to 30% in EDL (T30%). For definitions see Table 1 and for description see text.