title: Learning and memory alterations are associated with hippocampal N-acetylaspartate in a rat model of depression as measured by 1H-MRS.
abstract: It is generally accepted that cognitive processes, such as learning and memory, are affected in depression. The present study used a rat model of depression, chronic unpredictable mild stress (CUMS), to determine whether hippocampal volume and neurochemical changes were involved in learning and memory alterations. A further aim was to determine whether these effects could be ameliorated by escitalopram treatment, as assessed with the non-invasive techniques of structural magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Our results demonstrated that CUMS had a dramatic influence on spatial cognitive performance in the Morris water maze task, and CUMS reduced the concentration of neuronal marker N-acetylaspartate (NAA) in the hippocampus. These effects could be significantly reversed by repeated administration of escitalopram. However, neither chronic stress nor escitalopram treatment influenced hippocampal volume. Of note, the learning and memory alterations of the rats were associated with right hippocampal NAA concentration. Our results indicate that in depression, NAA may be a more sensitive measure of cognitive function than hippocampal volume.
authors.affiliation: Department of Neurology, Affiliated ZhongDa Hospital and the Institution Neuropsychiatry of Southeast University, Nanjing, Jiangsu, China.
authors.forename: Guangjun
authors.initials: G
authors.lastname: Xi
authors.forename: Jiaojie
authors.initials: J
authors.lastname: Hui
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Zhang
authors.forename: Shanshan
authors.initials: S
authors.lastname: Liu
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Zhang
authors.forename: Gaojun
authors.initials: G
authors.lastname: Teng
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Chan
authors.forename: Ed X
authors.initials: EX
authors.lastname: Wu
authors.forename: Binbin
authors.initials: B
authors.lastname: Nie
authors.forename: Baoci
authors.initials: B
authors.lastname: Shan
authors.forename: Lingjiang
authors.initials: L
authors.lastname: Li
authors.forename: Gavin P
authors.initials: GP
authors.lastname: Reynolds
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D015283:Citalopram / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D003401:Creatine / Q000378:metabolism; D003863:Depression / Q000150:complications / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D004195:Disease Models, Animal; D004327:Drinking Behavior / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D009929:Organ Size / Q000187:drug effects; D011522:Protons; D051381:Rats; D017207:Rats, Sprague-Dawley; D013315:Stress, Psychological / Q000150:complications / Q000378:metabolism / Q000503:physiopathology; D013395:Sucrose / Q000378:metabolism; D014867:Water
chemical_list: D011522:Protons; D014867:Water; D015283:Citalopram; D001224:Aspartic Acid; D013395:Sucrose; C000179:N-acetylaspartate; D003401:Creatine