FIGURE 1 . Autoradiographic film images of (A, B) dynorphin (DYN), (C, D) 
substance P (SP), and ( E , F) enkephalin (ENK) ISHH labeling in 
the striatum in a control (A, B, C) and cocaine self-administration 
animal (B, D, F). CP=caudate putamen, ACC=nucleus 
accumbens. 
SOURCE: Hurd et al. 1992 
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