Dynorphin (DYN) and KORs are widely distributed throughout the brain. In human brain tissue, high levels of prodynorphin mRNA have been observed in striatal (nucleus accumbens, caudate nucleus, putamen) and limbic (particularly the amygdala, entorhinal cortex, and dentate gyrus) regions (Hurd, 1996). An assessment of human KOR distribution in the brain revealed high expression of transcript throughout the cortex, amygdala, striatum (nucleus accumbens, caudate, putamen), thalamus, hypothalamus, and olfactory bulb (Simonin et al., 1995).
