Basic Neurobiology of Addiction

Neuropeptide Y

Neuropeptide Y (NPY) is a 36-amino-acid polypeptide that is also widely distributed throughout the central nervous system, with particularly high concentrations in the hypothalamus, periaqueductal gray, and extended amygdala (Figure 2.16). Administration of NPY directly into the brain increases feeding behavior, reduces anxiety-like behavior, and augments the effects of sedative hypnotics. The amygdala is a possible site that mediates the anti-stress effects of NPY. Multiple NPY receptor subtypes have been identified, and the Y1 and Y2 receptors have been the most implicated in stress actions. The Y1 receptor has a wide distribution in the rat brain. It is found most abundantly in the cortex, olfactory tubercle, hippocampus, hypothalamus, and thalamus. The distribution of Y2 receptors is similar to that of the Y1 receptors, although Y2 receptors are less abundant in the cortex and thalamus and more abundant in the hippocampus

Figure 2.16 Neuropeptide Y localization. Pathways hypothesized to be involved in NPY effects related to stress and emotionality. ARC, arcuate nucleus; Hipp, hippocampus; LC, locus coeruleus; LSdc, lateral septum-dorsocaudal; LSv, lateral septum-ventral; NAc, nucleus accumbens; PAG, periaqueductal gray matter. [Modified with permission from Heilig M. The NPY system in stress, anxiety and depression. Neuropeptides, 2004, (38), 213-224.]

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