Biophysical properties of Kv3.1 channels in SH-SY5Y human neuroblastoma cells

Biophysical properties of delayed rectifier K channels in the human neuroblastoma SH-SY5Y were established using patch clamp recordings. The whole cell K⁺ conductance activated at membrane potentials positive to -20 mV. The midpoint of current activation was 9.6 ± 5.1 mV, the equivalent charge was 3.7 ±.6. Whole-cell currents inactivated slightly with time constants of 700 ms and 5 s. The K⁺ currents were sensitive to micromolar concentrations of TEA and 4-aminopyridine. RT-PCR experiments amplified a cDNA fragment specific for human Kv3.1 channels. Activation gating parameters in outside-out patches were shifted by ∼14 mV in the hyperpolarizing direction.