Voltage-gated K⁺ currents recorded in w-t and Kv4.2−/− preoptic GABAergic neurons.

A. Voltage-gated K⁺ currents recorded in the presence of TTX (1 µM) in w-t (left) and Kv4.2−/− (right) neurons. The currents were elicited by the voltage step protocol depicted in the inset. Note the large I_DR present in the Kv4.2−/− neuron. B. Separation of I_A in the presence of TEA and 4-AP. The currents were elicited by the same voltage step protocol as in A. Recordings were from the same neurons as in A (upper traces). Lower traces represent the same traces on an expanded timescale. C. I–V plot for peak I_A amplitude in w-t (•) and Kv4.2−/− neurons (□) recorded in the presence of TEA and 4-AP. D. I–V plot for the steady state component of the current at the end of the depolarizing steps (Iss) in w-t (•) and Kv4.2−/− neurons (□) recorded in standard extracellular solution. C, D. Data points represent averages ±S.D. from n = 14 w-t neurons and n = 15 Kv4.2−/− neurons. The data points at −70, +10 and +20 mV are from a subset of n = 6 w-t neurons and n = 6 Kv4.2−/− neurons. E. I_A currents recorded in the presence of TEA and 4-AP in response to the voltage step protocol depicted in the inset. A depolarizing step to 0 mV was preceded by a 200 ms conditioning step to voltages ranging from −130 to −30 mV. F. Voltage-dependence of inactivation of I_A recorded in w-t (•, n = 8) and Kv4.2−/− neurons (□, n = 8). Data presented as averages ± S.D.