Ghrelin, a powerful orexigenic peptide released from the gut, stimulates feeding when
injected centrally and has thus far been implicated in regulation of metabolic, rather than
hedonic, feeding behavior. Although ghrelin's effects are partially mediated at the
hypothalamic arcuate nucleus, via activation of neurons that co-express neuropeptide Y and
agouti-related protein (NPY/Agrp neurons), the ghrelin receptor is expressed also in other
brain sites. One of these is the ventral tegmental area (VTA), a primary node of the …