Chapter 5 - Distribution of Multiple Opioid Receptors in the Human Brain

Abstract

Publisher Summary This chapter reviews a study on the respective distributions of mu, delta, and kappa opioid receptors in normal human brain and salient features of the localization of each opioid-receptor subtype in the human forebrain. The nucleus accumbens and the globus pallidus are moderately enriched with [3H]DAGO binding, which is surprising for the pallidal area because very low quantities of mu sites are found in these areas. The opioid peptides are present in high quantities in the pallidum and the presence of mu opioid binding sites in the region is expected. Very low amounts of specific delta binding sites are in the cerebellum which is highly enriched with mu sites, and important differences are observed between the localization of mu and delta sites in certain regions of the human brain. Various areas of the limbic system are highly enriched with kappa binding sites, including the amygdaloid body, amygdalo-hippocampal area, and the claustrum. Kappa opioid receptors are involved in the control of the activity of limbic system.