Kisspeptin increases GnRH neuron excitability in a time of day–dependent manner. A, Mean ± 75th percentile CI for spikes elicited during 500 ms current injection (0–30 pA, 2 pA steps) before (black symbols) and during (white symbols) kisspeptin treatment. Dotted area was used to calculate AUC for baseline measurements. Dotted area + solid area was used to calculate AUC for kisspeptin treatment. B–J, Mean ± 75th percentile CI before and during kisspeptin treatment. B, AUC. C, Percentage of cells firing within 1.5 s after termination of the current step. D, Spike latency. E, Threshold. F, Action potential amplitude. G, FWHM. H, Rate of rise. I, AHP amplitude. J, AHP time. When error bars are not visible, they are contained within the symbol. Lines connect means before and during kisspeptin. *p < 0.05, baseline versus kisspeptin (three-way, repeated-measures ANOVA/Bonferroni, or χ2) (C).