Expression of μ-opioid receptor in CA1 hippocampal astrocytes

Min Ho Nam, Kyung Seok Han, Jaekwang Lee, Jin Young Bae, Heeyoung An, Seahyung Park, Soo Jin Oh, Eunju Kim, Eunmi Hwang, Yong Chul Bae, C. Justin Lee

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


μ-opioid receptor (MOR) is a class of opioid receptors with a high affinity for enkephalins and beta-endorphin. In hippocampus, activation of MOR is known to enhance the neuronal excitability of pyramidal neurons, which has been mainly attributed to a disinhibition of pyramidal neurons via activating Gai subunit to suppress the presynaptic release of GABA in hippocampal interneurons. In contrast, the potential role of MOR in hippocampal astrocytes, the most abundant cell type in the brain, has remained unexplored. Here, we determine the cellular and subcellular distribution of MOR in different cell types of the hippocampus by utilizing MORmCherry mice and two different antibodies against MOR. Consistent with previous findings, we demonstrate that MOR expression in the CA1 pyramidal layer is co-localized with axon terminals from GABAergic inhibitory neurons but not with soma of pyramidal neurons. More importantly, we demonstrate that MOR is highly expressed in CA1 hippocampal astrocytes. The ultrastructural analysis further demonstrates that the astrocytic MOR is localized in soma and processes, but not in microdomains near synapses. Lastly, we demonstrate that astrocytes in ventral tegmental area and nucleus accumbens also express MOR. Our results provide the unprecedented evidence for the presence of MOR in astrocytes, implicating potential roles of astrocytic MOR in addictive behaviors.

Original languageEnglish
Pages (from-to)120-128
Number of pages9
JournalExperimental Neurobiology
Issue number2
Publication statusPublished - 2018 Apr 1

Bibliographical note

Funding Information:
This work was supported by the Creative Research Initiative Program (2015R1A3A2066619), World Class Institute (WCI 2009-003), MRC (2012-0000305), and Basic Science Research (2010-0029460) Programs of the National Research Foundation (NRF) funded by the Korean Ministry of Science and Technology (MEST).

Publisher Copyright:
© Experimental Neurobiology 2018.


  • Astrocyte
  • Electron microscopy
  • Hippocampus
  • μ-opioid receptor

ASJC Scopus subject areas

  • Clinical Neurology
  • Cellular and Molecular Neuroscience


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