Figure 4.
Blocking Ih alters membrane properties of GnRH neurons. A, Top, Representative current-clamp recordings showing the effect of a −50 pA current injection on GnRH neuron membrane potential. A characteristic sag develops during the injection and there is a rebound in membrane potential after termination of the current injection. ZD7288 blocks both the sag and rebound potentials. Bottom, Nickel fails to block the rebound, which is subsequently blocked by ZD7288. B, C, Voltage dependence of sag (B) and rebound (C) potentials in GnRH neurons (n = 11). D, E, Quantification of sag (D) and rebound (E) potentials before and during treatment with ZD7288 (n = 11). F, Relationship between sag and rebound potential in all cells studied. G, Response of GnRH neuron to 20 pA current injection under control (left) and ZD7288 (right) conditions showing that blocking Ih reduces excitability. H, Mean ± SEM spikes induced by a 40 pA current injection (n = 14, *p < 0.01). con, Control.