Figure 5.

Effect on outward currents of blockade of Kv3.4 and Kv4 subunits

A, peak current plot of outward currents recorded in CB chemoreceptor cells after application of depolarizing steps to +40 mV every 20 s. The bath application of the BDS-I toxin reversibly decreases the peak current. The upper right panel shows representative recordings made under different experimental conditions, and the subtracted recording of control/toxin currents. The lower right panel shows the plot of the average (mean ± s.e.m.) percent inhibition, and time course (τ) of the subtracted current. B, the upper panel plots the average inhibition of outward currents after bath application of heteropodatoxin (HpTx-2). The lower panel shows representative recordings of chemoreceptor outward currents. In this case, transient outward currents were elicited (under control and toxin application conditions) by depolarizing steps to +40 mV following 10 s prepulses to two different potentials, −80 mV (to obtain the fully primed current) and 0 mV (to inactivate the transient component). The fast-inactivating current was defined as the difference between the currents elicited by the two pulses.