title: Effects of Chronic Scopolamine Treatment on Cognitive Impairments and Myelin Basic Protein Expression in the Mouse Hippocampus.
abstract: Myelin plays an important role in learning and memory, and degradation of myelin is a key feature in the pathogenesis of neurological disorders involving cognitive dysfunction. Myelin basic protein (MBP) is one of the most abundant structural proteins in myelin and is essential for myelin formation and compaction. In this study, we first examined changes in the distribution of MBP-immunoreactive myelinated fibers and MBP levels according to hippocampal subregion in mice following chronic systemic treatment with 1 mg/kg scopolamine (SCO) for 4 weeks. We found that SCO-induced cognitive impairments, as assayed by the water maze and passive avoidance tests, were significantly reduced 1 week after SCO treatment and the impairments were maintained without any hippocampal neuronal loss. MBP-immunoreactive myelinated fibers were easily detected in the stratum radiatum and lacunosum-moleculare of the hippocampus proper (CA1-3 region) and in the molecular and polymorphic layers of the dentate gyrus. The distribution of MBP-immunoreactive myelinated fibers was not altered 1 week after SCO treatment. However, the density of MBP-immunoreactive myelinated fibers was significantly decreased 2 weeks after SCO treatment; thereafter, the density gradually, though not significantly, decreased with time. In addition, the changing pattern of MBP levels in the hippocampus following SCO treatment corresponded to immunohistochemical changes. In brief, this study shows that chronic systemic treatment with SCO induced significant degradation of MBP in the hippocampus without neuronal loss at least 2 weeks after SCO treatment, although cognitive impairments occurred 1 week after SCO treatment.
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 24341, South Korea.
authors.forename: Joon Ha
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Emergency Medicine, Gangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, 07441, South Korea.
authors.forename: Hyun Young
authors.initials: HY
authors.lastname: Choi
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 24341, South Korea.
authors.forename: Jeong-Hwi
authors.initials: JH
authors.lastname: Cho
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 24341, South Korea.
authors.forename: In Hye
authors.initials: IH
authors.lastname: Kim
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 24341, South Korea.
authors.forename: Tae-Kyeong
authors.initials: TK
authors.lastname: Lee
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 24341, South Korea.
authors.forename: Jae-Chul
authors.initials: JC
authors.lastname: Lee
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 24341, South Korea. mhwon@kangwon.ac.kr.
authors.forename: Moo-Ho
authors.initials: MH
authors.lastname: Won
authors.affiliation: Department of Physiology, College of Medicine, and Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon, 24252, South Korea.
authors.forename: Bai Hui
authors.initials: BH
authors.lastname: Chen
authors.affiliation: Department of Physiology, College of Medicine, and Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon, 24252, South Korea.
authors.forename: Bich-Na
authors.initials: BN
authors.lastname: Shin
authors.affiliation: Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, 24252, South Korea.
authors.forename: Ji Hyeon
authors.initials: JH
authors.lastname: Ahn
authors.affiliation: Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, 24252, South Korea.
authors.forename: Hyun-Jin
authors.initials: HJ
authors.lastname: Tae
authors.affiliation: Department of Anatomy, College of Veterinary Medicine, Kangwon National University, Chuncheon, 24341, South Korea.
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Choi
authors.affiliation: Department of Veterinary Internal Medicine, College of Veterinary Medicine, Kangwon National University, Chuncheon, 24341, South Korea.
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Chung
authors.affiliation: Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan, 31116, South Korea.
authors.forename: Choong-Hyun
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, 24341, South Korea.
authors.forename: Jun Hwi
authors.initials: JH
authors.lastname: Cho
authors.affiliation: Department of Food Science and Nutrition, Hallym University, Chuncheon, 24252, South Korea.
authors.forename: Il Jun
authors.initials: IJ
authors.lastname: Kang
authors.affiliation: Division of Food Biotechnology, School of Biotechnology, Kangwon National University, Chuncheon, 24341, South Korea. jongdai@kangwon.ac.kr.
authors.forename: Jong-Dai
authors.initials: JD
authors.lastname: Kim
mesh_terms: D000818:Animals; D060825:Cognitive Dysfunction / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D004676:Myelin Basic Protein / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D012601:Scopolamine / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity
chemical_list: D018727:Muscarinic Antagonists; D004676:Myelin Basic Protein; D012601:Scopolamine
keywords: Cognitive deficit; Dentate gyrus; Hippocampus proper; Myelin basic protein; Myelinated nerve fibers; Scopolamine