Fig. 3. Two types of voltage-gated K⁺ channel (Kv) currents in CD34⁺ HSCs. Membrane current responses to step-like depolarization (300 ms of voltage steps between -120 and 100 mV; 20 mV interval) from -80 mV of holding voltage (see inset). Representative traces of Kv current demonstrate time-dependent inactivation (A) and sustained activity (B). The inactivating type of Kv currents were sensitive to 4-AP (5 mM, A) whereas the non-inactivating types were insensitive to 4-AP (B). The amplitudes of peak currents were normalized to the membrane capacitance (pA/pF), and the mean values are summarized as current:voltage relations [I/V curves, right panels, n = 8 and 7 for (A) and (B), respectively]. *, P < 0.05.