Fig. 5. Responses of a GnRH neuron to hyperpolarizing and depolarizing current and voltage pulses. A, Passive and active responses to 1 sec current pulses of −50, −40, −30, −20, −10, 0, 10, and 20 pA of a GFP-expressing GnRH neuron in the DBB of the 6-month-old female GnRH-GFP mouse from which the recording in Figure 4H was obtained. B, Maximum firing evoked by a 1 sec depolarizing current pulse of 40 pA in the GnRH neuron whose responses are shown in A.C, High-resolution recording of an action potential evoked by a 20 msec depolarizing current pulse of 40 pA in the same GnRH neuron. Resting, threshold, peak, half-amplitude, and afterhyperpolarization potentials are indicated. D, Voltage-gated currents in the same GnRH neuron in response to 10 msec voltage pulses from a Vh of −60 mV to test potentials of −140, −120, −100, −80, −60, −40, −20, 0, 20, 40, 60, and 80 mV.