Fig. 3.

Intrinsic membrane properties of four types (I–IV) of GnRH neurons recorded in adult female mice.A–D, Responses to 20 and 200 msec depolarizing and hyperpolarizing current pulses. In all four cell types, threshold stimulation elicited a single action potential, which clearly shows depolarizing afterpotential (ADP) of various duration and amplitude. In each cell type, 200 msec duration hyperpolarizing current injection revealed the presence of inward rectifiers with distinct kinetics. The four cell types are characterized on the basis of their inward rectification as well as the absence of rebound depolarization in type II cells and the inability to fire repetitively after depolarization in type III cells. Resting membrane potentials are given for each cell.