(A) Activation curves of the delayed rectifier K+ current (I
K) prior to and during superfusion with 100 µM (±) SKF83959 (n = 8). (B) Steady-state inactivation curves of I
K prior to and during superfusion with 100 µM (±) SKF83959 (n = 8). (C) Time courses of recovery of I
K from inactivation prior to and during superfusion with 100 µM (±) SKF83959 (n = 6). For studying the activation, neurons were held at −50 mV, currents were elicited with a series of 400-ms step from −80 mV to +80 mV in 10 mV increments following a 600-ms hyperpolarizing prepulse to −110 mV and a 50-ms interval at −50 mV, delivered every 10 s. For studying the steady-state inactivation, neurons were held at 0 mV, currents were elicited with a series of 600-ms prepulses at different hyperpolarizing potentials followed by a 50-ms interval at −50 mV and a 400-ms step to +40 mV, then back to 0 mV, delivered every 10 s. For studying the time course of recovery from inactivation, neurons were held at 0 mV, currents were elicited on return from hyperpolarizing prepulses of varying durations at −110 mV to +40 mV, delivered every 10 s.