Figure 1.

Orexin excites ARC Type-C neurons. A, Cell-attached patch-clamp recordings in the absence and presence of orexin-A (100 nm). B, Whole-cell recording from the same cell revealed a delayed excitation after hyperpolarizing current injection in current-clamp (left; the dashed line indicates the zero potential) and a low-threshold transient outward current in voltage-clamp (right; holding potential -90 mV, depolarizing steps from -80 to -30 mV in 10 mV increments), the defining features of Type-C neurons (see Results). C, Orexin-A (100 nm) excited ARC Type-C neurons; whole-cell current-clamp recording. Action potentials are truncated at 0 mV.