Fig. 1.

Properties of K_Ca currents in E11 LMNs. A, Outward currents were evoked in control and Ca²⁺-free saline (left traces) by 25 msec depolarizing pulses to +30 mV from a holding potential of −40 mV (bottom left). Net macroscopic K_Ca was obtained after digital subtraction of raw traces (right trace). B, Mean macroscopic K_Caconductance as a function of voltage in 13 LMNs. A decline in conductance at command potentials positive to +50 is predicted for a Ca²⁺-dependent current. C, Effect of iberiotoxin (200 nm) and apamin (1 μm) on macroscopic K_Ca currents. Dissociated E11 LMNs were treated with these toxins for at least 30 min before whole-cell recordings. Control LMNs were not exposed to toxins before recording.