Figure 5.

Voltage-dependent activation of the anti-Kv2.1-sensitive current Outward K⁺ currents were activated by series of depolarizing voltages in 10 mV increments from a holding potential of –70 mV (A–D) or –90 mV (E–H). A, example of currents recorded from one pyramidal cell just after break in to whole-cell mode (P20). Note the small fast, transient current (A-type: arrow). B, currents recorded at 6 min from the same cell. Because the slowly activating current was reduced, the A-type current was more obvious (arrow). C, subtraction of records in B from those in A reveals the antibody-sensitive current (inset: voltage protocol). D, steady-state activation curves for the non-A-type current components were obtained by fitting peak current amplitudes to the Boltzmann equation. The antibody (AB)-sensitive currents (•), obtained by subtracting the currents at 6–9 min from the currents at 0 min, had a half-activation potential of +3.8 mV with a slope of 13.4 mV. The remaining current (▾) activated at more negative potentials than the AB-sensitive current (half-activation at –3 mV, slope = 14.2 mV). E, representative traces for currents just after break-in from another cell (P28). In this cell, currents were elicited by steps to various potentials after a prepulse to –90 mV for 3 s (to remove inactivation, see inset in G). F, currents in the same cell after 6 min diffusion of polyclonal anti-Kv2.1. G, subtracted records (E −F) to indicate the AB-sensitive current (inset: voltage protocol). H, steady-state activation curve for averaged data from 3 cells using the protocol in G. The anti-Kv2.1-sensitive current had a V_1/2 of +0.1 mV (slope, 13.2 mV). The remaining current activated at more negative potentials (V_1/2, = −17 mV; slope, 15.7 mV).