CTB labels many non-POMC cells and few POMC cells.

<p>(A & B) Example images after CTB injection into the SON. (A) Low-power image in the arcuate nucleus shows POMC neurons (red) and CTB-containing neurons (green). The side of the arcuate corresponding to the side of injection (ipsilateral) has more intense CTB labeling compared to the contralateral side. (B) Higher magnification image taken in the ipsilateral side shows POMC neurons with (white arrows) and without CTB label. Many neurons contain CTB, but not POMC-DsRed. 3V = 3rd ventricle. (C) Graph showing the number of cells imaged that have CTB after injections into the various target sites (white bars). The number of CTB-positive cells that also express POMC-DsRed are shown in the red portion of the bars. Solid bars correspond to counts from the side of the arcuate nucleus ipsilateral to the injection; striped bars correspond to the contralateral side. Data are presented as mean ± SEM. The numbers in parentheses indicate the number of animals in each group. The asterisks denote p<0.05 compared to ipsilateral side for same injection target. Abbreviations: SON, supraoptic nucleus; PVN, paraventricular nucleus; LH, lateral hypothalamic area; VTA, ventral tegmental area; PAG, periaqueductal gray; BST, bed nucleus of the stria terminalis; Amyg, amygdala; DVC, dorsal vagal complex.