Nam, Min-Ho Han, Kyung-Seok Lee, Jaekwang Bae, Jin Young An, Heeyoung Park, Seahyung Oh, Soo-Jin Kim, Eunju Hwang, Eunmi Bae, Yong Chul Lee, C. Justin 2024-01-19T23:03:13Z 2024-01-19T23:03:13Z 2021-09-03 2018-04 1226-2560 https://pubs.kist.re.kr/handle/201004/121558 mu-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 MORm-Cherry 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. English KOREAN SOC BRAIN & NEURAL SCIENCE, KOREAN SOC NEURODEGENERATIVE DISEASE GABAERGIC NEURONS RAT HIPPOCAMPUS INTERNEURONS ACTIVATION TOLERANCE MORPHINE BRAIN DELTA AREA Expression of mu-Opioid Receptor in CA1 Hippocampal Astrocytes Article 10.5607/en.2018.27.2.120 1 EXPERIMENTAL NEUROBIOLOGY, v.27, no.2, pp.120 - 128 EXPERIMENTAL NEUROBIOLOGY 27 2 120 128 scie scopus kci ART002345427 000433039400006 2-s2.0-85046487351 Medicine, Research & Experimental Neurosciences Research & Experimental Medicine Neurosciences & Neurology Article GABAERGIC NEURONS RAT HIPPOCAMPUS INTERNEURONS ACTIVATION TOLERANCE MORPHINE BRAIN DELTA AREA Astrocyte Electron microscopy Hippocampus mu-opioid receptor