Expressed channel | Activation (outside-out patch) | Relaxation (inside-out patch) | Time to peak current (outside-out patch) | Time to peak current (two-electrode voltage clamp, oocytes) |
---|---|---|---|---|
hSlo | τ1 = 1.17 msec ± 0.25 | τ1 = 2.57 msec ± 0.39 | 28.7 msec ± 5.8 | 11.76 msec ± 0.86 |
τ2 = 10.78 msec ± 3.02 | τ2 = 15.78 msec ± 4.35 | |||
n = 7 | n = 5 | n = 7 | n = 5 | |
hSlo + hSloβ | τ1 = 9.27 msec ± 0.83** | τ1 = 4.01 msec ± 0.50* | 145.6 msec ± 19.6* | 24.24 msec ± 1.55** |
τ2 = 48.89 msec ± 12.10** | τ2 = 28.37 msec ± 9.14 | |||
n = 4 | n = 4 | n = 6 | n = 5 |
Several methods were used to examine the relative activation rates of hSlo and hSlo + hSloβ BK channels in HEK 293 cells and oocytes. Current activation and relaxation kinetics were best fit using a two-component exponential model of the form y = A1 × exp[− (t − to)/τ1] + A2 × exp[− (t − to)/τ2] + C(see text). Time to peak currents were directly measured. Values given for oocyte times to peak current are for a voltage step between −60 and 140 mV; details of all other recordings are given in the description of experimental procedures. All values are mean ± SEM. Comparisons are two-tailed t tests. hSlo + hSloβ versus hSlo, *p < 0.05, **p < 0.005.