Properties of fluo-4 signals in toadfish swimbladder fibers (16°C)
| Parameter | 1 AP (mean ± SEM; n) | 40 APs at 83 Hz (mean ± SEM; n) |
| A: Early signal | ||
| 10–100% rise time (ms) | 2.6 ± 0.1; 10 | – |
| Peak ΔF/FR | 28.7 ± 2.0; 5 | – |
| FDHM (ms) | 15.1 ± 0.5; 10 | – |
| B: Late signal amplitudes | ||
| ΔF(1 s)/ΔF1 | 0.030 ± 0.003; 5 | 0.263 ± 0.014; 7 |
| ΔF(60 s)/ΔF1 | 0.009 ± 0.003; 5 | 0.024 ± 0.005; 7 |
| C: Fitted values, 1–60 s | ||
| A1 (ΔF/F1) | 0.021 ± 0.002; 5 | 0.119 ± 0.011; 7 |
| τ1 (s) | 23.3 ± 2.5; 5 | 1.85 ± 0.10; 7 |
| A2 (ΔF/F1) | – | 0.112 ± 0.008; 7 |
| τ2 (s) | – | 10.7 ± 0.9; 7 |
| Offset (ΔF/F1) | 0.007 ± 0.004; 5 | 0.023 ± 0.005; 7 |
| Parameter | 1 AP (mean ± SEM; n) | 40 APs at 83 Hz (mean ± SEM; n) |
| A: Early signal | ||
| 10–100% rise time (ms) | 2.6 ± 0.1; 10 | – |
| Peak ΔF/FR | 28.7 ± 2.0; 5 | – |
| FDHM (ms) | 15.1 ± 0.5; 10 | – |
| B: Late signal amplitudes | ||
| ΔF(1 s)/ΔF1 | 0.030 ± 0.003; 5 | 0.263 ± 0.014; 7 |
| ΔF(60 s)/ΔF1 | 0.009 ± 0.003; 5 | 0.024 ± 0.005; 7 |
| C: Fitted values, 1–60 s | ||
| A1 (ΔF/F1) | 0.021 ± 0.002; 5 | 0.119 ± 0.011; 7 |
| τ1 (s) | 23.3 ± 2.5; 5 | 1.85 ± 0.10; 7 |
| A2 (ΔF/F1) | – | 0.112 ± 0.008; 7 |
| τ2 (s) | – | 10.7 ± 0.9; 7 |
| Offset (ΔF/F1) | 0.007 ± 0.004; 5 | 0.023 ± 0.005; 7 |
The entries were determined on fibers that had been rested for at least 3 min before stimulation; n indicates the number of experiments. A dashed entry means the value was not determined or not well known. In A, the amplitude of ΔF/FR, which has been referred to the myofibrillar region of the fiber, could not be determined in all experiments because the intrinsic fluorescence of the bundle interfered with the determination of FR (see Materials and methods); however, the time course of ΔF was well known in most fibers because of the generally large signal/noise ratio of ΔF. In B, the entries give the value of ΔF measured at either 1 or 60 s after onset of stimulation divided by ΔF1, the peak of ΔF elicited by the first stimulated AP. In C, the entries were obtained from a least-squares fit of one of the following equations to the temporal waveform of ΔF(t)/ΔF1: (a) with 1 AP, ΔF(t)/ΔF1 = A1 · exp(−t/τ1) + offset; (b) with 40 APs at 83 Hz, ΔF(t)/ΔF1 = A1 · exp(−t/τ1) + A2 · exp(−t/τ2) + offset.