Table 1.

Activation and relaxation kinetics of hSlo andhSlo + hSloβ

Expressed channelActivation (outside-out patch)Relaxation (inside-out patch)Time to peak current (outside-out patch)Time to peak current (two-electrode voltage clamp, oocytes)
hSloτ1  = 1.17 msec ± 0.25τ1  = 2.57 msec ± 0.3928.7 msec ± 5.811.76 msec ± 0.86
τ2  = 10.78 msec ± 3.02τ2  = 15.78 msec ± 4.35
n = 7n = 5n = 7n = 5
hSlo + hSloβτ1  = 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 = 4n = 4n = 6n = 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.