In this light microscopic immunocytochemical study beta-Endorphin (beta-END), leu-enkephalin and dopamine-beta hydroxylase (DBH) antisera are used to obtain an overview of the interaction of the noradrenergic and opiate peptide systems in brain. Serial brain areas were analyzed for DBH and then for beta-END or leu-enkephalin. Several areas were evaluated for cell and fiber interactions between these systems. The areas of richest possible contact between beta-END and DBH positive systems include the rostral locus coeruleus region, the periaqueductal grey, possibly the dorsal thalamus, the paraventricular hypothalamus and the arcuate nucleus. Enkephalin cells and fibers were seen surrounding the locus coeruleus throughout its length with a few fibers in the nucleus itself.