Activation and Decay of Ca2+ Transients during Local Depolarizations
. | ΔF/F (ΔF/F) . | tpeak (s) . | t1/2 decay (s) . | r20 (%) . | |||
|---|---|---|---|---|---|---|---|
| normal (2 mM Ca2+) | 3.25 ± 0.35 (24) | 3.76 ± 0.34 | 10.64 ± 0.98 | 31.92 ± 5.03 | |||
| normal (0 mM Ca2+) | 1.31 ± 0.15a (12) | 1.97 ± 0.22b | 4.98 ± 0.45a | 4.36 ± 2.38a | |||
| normal + 100 μM Gd3+(2 mM Ca2+) | 1.77 ± 0.18b (14) | 1.94 ± 0.13a | 3.49 ± 0.47a | 2.23 ± 0.74a | |||
| dysgenic + SkEIIIK (2 mM Ca2+) | 0.90 ± 0.18a (9) | 3.51 ± 0.50 | 4.47 ± 0.52a | 10.41 ± 2.70c | |||
| dysgenic + SkEIIIK (0 mM Ca2+) | 0.25 ± 0.09a (5) | 2.70 ± 0.45 | 5.68 ± 1.12c | 4.97 ± 2.17c | |||
| dysgenic (2 mM Ca2+) | no response (12) | ||||||
| dyspedic (2 mM Ca2+) | no response (14) | ||||||
| β1 null (2 mM Ca2+) | no response (10) | ||||||
| dysgenic + SkEIIIK + ryanodine (2 mM Ca2+) | no response (20) | ||||||
. | ΔF/F (ΔF/F) . | tpeak (s) . | t1/2 decay (s) . | r20 (%) . | |||
|---|---|---|---|---|---|---|---|
| normal (2 mM Ca2+) | 3.25 ± 0.35 (24) | 3.76 ± 0.34 | 10.64 ± 0.98 | 31.92 ± 5.03 | |||
| normal (0 mM Ca2+) | 1.31 ± 0.15a (12) | 1.97 ± 0.22b | 4.98 ± 0.45a | 4.36 ± 2.38a | |||
| normal + 100 μM Gd3+(2 mM Ca2+) | 1.77 ± 0.18b (14) | 1.94 ± 0.13a | 3.49 ± 0.47a | 2.23 ± 0.74a | |||
| dysgenic + SkEIIIK (2 mM Ca2+) | 0.90 ± 0.18a (9) | 3.51 ± 0.50 | 4.47 ± 0.52a | 10.41 ± 2.70c | |||
| dysgenic + SkEIIIK (0 mM Ca2+) | 0.25 ± 0.09a (5) | 2.70 ± 0.45 | 5.68 ± 1.12c | 4.97 ± 2.17c | |||
| dysgenic (2 mM Ca2+) | no response (12) | ||||||
| dyspedic (2 mM Ca2+) | no response (14) | ||||||
| β1 null (2 mM Ca2+) | no response (10) | ||||||
| dysgenic + SkEIIIK + ryanodine (2 mM Ca2+) | no response (20) | ||||||
Data presented here were obtained with depolarizations evoked by 20-s applications of 80 mM KCl Ringer's solution via a micropipette placed near the cell of interest. Where indicated, 100 μM Gd3+ was added to the 80 mM KCl Ringer's solution in the micropipette. See Materials and methods for definitions of tpeak, t1/2 decay, and r20. Data are given as mean ± SEM, with the numbers in parentheses indicating the number of myotubes tested. Footnotes indicate significant differences compared to normal myotubes in 2 mM Ca2+ by unpaired t test:
P < 0.001.
P < 0.005.
P < 0.05.