The comparison between enkephalin-like and dynorphin-like immunoreactivity in both monkey and human globus pallidus and substantia nigra.

The distribution of [Met]-Enkephalin and Dynorphin-like immunoreactivity were studied in the monkey and human globus pallidus and substantia nigra. These distributions were compared to those seen in these structures of the rat. Interspecies variations were observed in the substantia nigra, and in both pallidal segments. Differences between the distribution of the two opiate peptides occurred mostly in the limbic-related globus pallidus.