Contrasting excitability profiles of Ah-type VGN from intact and OVX adult female rats. Differential AP firing patterns of VGN classified as myelinated Ah type between intact (normal; n = 44) and OVX (n = 51) female rats are shown. A suprathreshold 300-pA step current depolarization of 1,000 ms elicited 1 of 3 patterns of excitability: repetitive, burst, and, in rare cases, only a single AP. The contrasting distributions of these 3 patterns of excitability emphasize the impact OVX has on reducing the excitability of Ah-type VGN in OVX rats.