Figure 7. Distribution of retrogradely labelled neurons in the hypothalamus following cholera toxin b subunit injection into the rostral raphe pallidus.

Schematic diagrams in A and D show locations of cholera toxin subunit b (CTb)-containing (green circles), orexin-immunoreactive (red circles) and double-labelled (black dots) neurons following CTb injection into the rostral raphe pallidus (RPa) (B and E) of wild-type mice (A–C) and orexin neuron-ablated mice (D–F). Results in four animals (one typical specimen per animal) were plotted on an atlas drawing. C and F, representative photographs in WT mice and orexin neuron-ablated mice, respectively. C′, of orexin-immunoreactive nerve terminals (arrow) attaching to the CTb-positive cell found in the dorsal hypothalamic area (DHA) in a wild-type mouse. DMH, dorsomedial hypothalamus; f, fornix; FN, facial nucleus; LHA, lateral hypothalamic area; mt, mammillary tract; PeF, perifornical area; Py, pyramidal tract.