NPY is a highly-conserved 36 amino-acid peptide (de Quidt and Emson, 1986; Sundler et al., 1986) and has multiple functions including anxiolytic regulation (Heilig and Thorsell, 2002), food intake stimulation (Clark et al., 1984; Jolicoeur et al., 1991; Zarjevski et al., 1993), and neuronal excitability (Woldbye et al., 1996). NPY is abundant in the cortex, striatum, nucleus accumbens, amygdala, and hypothalamus (Badia-Elder et al., 2007; Gray and Morley, 1986; Heilig and Widerlov, 1995; Spence et al., 2005).
