Comparison of potassium currents in outside-out patches from dendrites and somata of cerebellar Purkinje neurons
| Parameter | Dendrite | Soma |
|---|---|---|
| Activation | ||
| Midpoint | -10 ± 2 mV (n = 16) | -12 ± 2 mV (n = 18) |
| k/4 | 5.8 ± 0.3 mV (n = 16) | 4.5 ± 0.3 mV (n = 18) |
| τ(0 mV) | 3.1 ± 0.4 msec (n = 16) | 4.3 ± 0.5 msec (n = 18) |
| τ(20 mV) | 2 ± 0.1 msec (n = 16) | 1.9 ± 0.2 msec (n = 18) |
| Deactivation | ||
| τ(-70 mV) | 1.1 ± 0.2 msec (n = 4) | 0.8 ± 0.2 msec (n = 7) |
| τ(-40 mV) | 2.8 ± 0.9 msec (n = 4) | 2.8 ± 0.4 msec (n = 7) |
| Inactivation | ||
| Vh | -37.6 ± 4.5 mV (n = 6) | -38.8 ± 4.3 mV (n = 7) |
| k | 12 ± 0.6 mV (n = 6) | 15.6 ± 1.2 mV (n = 7) |
| τfast | 18.7 ± 3.3 msec (n = 26) | 14 ± 2.5 msec (n = 15) |
| Noninactivating (100 msec) | 55 ± 2% (n = 28) | 75 ± 2% (n = 28) |
| Block by 1 mm TEA | 76 ± 4% (n = 10) | 79 ± 3% (n = 9) |
All data are from outside-out patches except the data for inactivation of somatic currents, which are from outside-out nucleated patches. The voltage dependence of the inactivation curve was determined using a 5 sec prepulse. For dendrites, data were confined to patches at a distance from soma of at least 100 μm for activation and inactivation and at least 70 μm for TEA block. Parameters reported in this table were obtained by averaging values from fitting of individual experiments.