Table 3.
Stretch activation magnitude of Drosophila jump muscle fibers
| Pi, mM | ASA, mN/mm2 | PSA, mN/mm2 | FSA, mN/mm2 | FSA/F0 | n | |
|---|---|---|---|---|---|---|
| Control | 0 | 3.9 ± 0.4 | 0.7 ± 0.2 | 3.2 ± 0.5 | 0.08 ± 0.02 | 7 |
| 8 | 3.8 ± 0.4 | 1.2 ± 0.3 | 2.6 ± 0.5 | 0.12 ± 0.02 | 10 | |
| 16 | 2.6 ± 0.5* | 1.1 ± 0.3 | 1.5 ± 0.5* | 0.09 ± 0.03 | 10 | |
| IFI | 0 | 3.8 ± 0.3 | 1.3 ± 0.2 | 2.6 ± 0.4 | 0.09 ± 0.02 | 9 |
| 8 | 4.6 ± 0.3 | 1.5 ± 0.3 | 3.2 ± 0.4 | 0.18 ± 0.04 | 9 | |
| 16 | 4.0 ± 0.3# | 1.5 ± 0.3 | 2.6 ± 0.4# | 0.16 ± 0.04# | 9 |
Values are means ± SE. n, no. of fibers; ASA, total stretch-activated tension measured at pCa 5.0; PSA, passive component of stretch-activated tension measured at pCa 8.0; FSA, net stretch-activated tension (FSA = ASA – PSA).
*
Statistically significant compared with 0 mM Pi, P < 0.05 (Student’s t-test).
#
Statistically significant compared with the control value at the given Pi concentration, P < 0.05 (Student’s t-test).