Neuroanatomical distribution of μ-opioid receptor mRNA and binding in monogamous prairie voles (Microtus ochrogaster) and non-monogamous meadow voles (Microtus pennsylvanicus)

• Type of Material: Article
• Authors: Kiyoshi Inoue, Emory University; James P. Burkett, Emory University; Larry Young, Emory University
• Language: English
• Date: 2013-08-06
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.neuroscience.2013.03.035
• Title of Journal or Parent Work: Neuroscience
• ISSN: 0306-4522
• Volume: 244
• Start Page: 122
• End Page: 133
• Grant/Funding Information: This work was funded in part by NIH Grant MH64692 to LJY.; Additional support was provided by the National Center for Research Resources P51RR165 to YNPRC, which is currently supported by the Office of Research Infrastructure Programs/OD P51OD11132; and the Emory Scholars Program in Interdisciplinary Neuroscience Research to JPB.
• Keywords: SEPARATION DISTRESS; GENE OPRM1; SOCIAL ATTACHMENT; pair bonding; Science & Technology; social behavior; social attachment; RHESUS-MONKEYS; Life Sciences & Biomedicine; AFFILIATIVE BEHAVIOR; SEX-DIFFERENCES; NUCLEUS-ACCUMBENS; Neurosciences; POLYGAMOUS VOLES; Neurosciences & Neurology; KNOCKOUT MICE; PARTNER PREFERENCE
• Research Categories: Biology, Zoology; Biology, Neuroscience

Abstract

The opiate system has long been implicated in the rewarding properties of social interactions. In particular, the μ-opioid receptor (MOR) mediates multiple forms of social attachment, including the attachment of offspring to the mother and social bonding between mates. We have previously shown that MOR in the caudate-putamen is involved in partner preference formation in monogamous prairie voles. Here, using in situ hybridization and receptor autoradiography, we mapped in detail the distribution of MOR mRNA and ligand binding in monogamous prairie vole brains and compared MOR binding density with that of promiscuous meadow vole brains. Comparison of MOR binding in these closely related species with distinctly different social behavior revealed that while the distribution of MOR is similar, prairie voles have significantly higher densities of MOR than meadow voles in a majority of regions in the forebrain, including the caudate-putamen, nucleus accumbens shell, lateral septum and several thalamic nuclei, including the anteroventral and anteromedial thalamic nuclei. These differences in MOR expression between prairie and meadow voles could potentially contribute to species differences in behavior, including social attachment.