Table 3.
Effects of 0.2 mm DIDS on action potential characteristics of SA node cells expressing ICl(Ca) (n = 6) in the presence of adrenergic receptor stimulation by 1 μM noradrenaline
| Control | Norad. | Norad. + DIDS | |
|---|---|---|---|
| APD20 (ms) | 72 ± 7 | 61 ± 4* | 70 ± 5† |
| APD50 (ms) | 105 ± 11 | 94 ± 7 | 100 ± 6 |
| APD100 (ms) | 160 ± 11 | 153 ± 5 | 155 ± 5 |
| MDP (mV) | −62.0 ± 1.2 | −61.4 ± 2.0 | −61.6 ± 1.5 |
| DDR (mV s−1) | 91 ± 17 | 117 ± 17* | 118 ± 17 |
| Overshoot (mV) | 19.3 ± 1.2 | 16.4 ± 1.3* | 21.9 ± 1.6† |
| dV/dtmax (V s−1) | 5.4 ± 0.6 | 6.8 ± 0.4* | 6.6 ± 0.3 |
| Cycle length (ms) | 339 ± 16 | 267 ± 24* | 270 ± 19 |
Data are means ± s.e.m.. APD20, APD50, and APD100, action potential duration at 20, 50, and 100 % repolarization, respectively. MDP, maximal diastolic potential; DDR, diastolic depolarization rate; Overshoot, action potential overshoot; and dV/dtmax, maximum upstroke velocity, Norad., noradrenaline.
*
P < 0.05 noradrenaline vs. control
†
P < 0.05 noradrenaline + DIDS vs. noradrenaline.