Figure 8.

K⁺_LVA channels mediate the majority of Flx-insensitive K_V current and regulate neural excitability. (A) Steady-state K_V current traces recorded from an E19 NM neuron before (control) and during subsequent bath application of Flx and DTx (0.1 μM). DTx is a potent K_V1.1, K_V1.2-containing K⁺_LVA channel blocker. Data obtained during drug application are shown in red. Symbols (square and circles) at the end of current traces represent time window of measured steady-state K_V currents. (B) Current-voltage relationship before and during subsequent drug application for the E19 NM neuron shown in (A). Note that data points at −100 mV are not shown for simplicity. (C) Representative voltage traces recorded from an E15 NM neuron before and during DTx application, in response to a sequence of sustained current injections (current step = 20 pA, current duration = 100 ms). (D) Population data showing the number of APs recorded from NM neurons at E14–16 and counted under different conditions: control (Cont) or during DTx application (DTx), in response to threshold (Thres) or suprathreshold injected current (SThres). Inset is the population data showing a significant reduction in threshold current before and during DTx application. Open circles represent an individual neuron and solid bars represent the average for each age group. *p < 0.05, Bonferroni adjusted t-test.