Comparative distribution of opiate receptors and three opioid peptide neuronal systems in rhesus monkey central...

Using combined autoradiography-immunocytochemistry, the anatomical distribution of [3H]naloxone-labelled opiate receptors was compared to the loci of neuronal systems immunoreactive for beta-endorphin, [Leu]enkephalin and dynorphin A in rhesus monkey brain. High densities of binding were observed in relation to each of the systems, consistent with findings that each opioid precursor can synthesize one or more peptides with substantial (though not selective) activity at mu receptors.