title: Increased postsynaptic density protein-95 expression in the frontal cortex of aged cognitively impaired rats.
abstract: In the present work we studied synaptic protein concentrations in relation to behavioral performance. Long-Evans rats, aged 22-23 months, were classified for individual expression of place memory in the Morris water maze, in reference to young adults. Two main subgroups of aged rats were established: the Aged cognitively Unimpaired (AU) had search accuracy within the range (percent of time in training sector within mean ± 2 SEM) of young rats and the Aged cognitively Impaired (AI) rats had search accuracy below this range. Samples from the hippocampus and frontal cortex of all the AI, AU and young rats were analyzed for the expression of postsynaptic protein PSD-95 by Image J analysis of immunohistochemical data and by Western blots. PSD-95 expression was unchanged in the hippocampus, but, together with synaptophysin, was significantly increased in the frontal cortex of the AI rats. A significant correlation between individual accuracy (time spent in the training zone) and PSD-95 expression was observed in the aged group. No significant effect of age or PSD-95 expression was observed in the learning of a new position. All together, these data suggest that increased expression of PSD-95 in the frontal cortex of aged rats co-occurs with cognitive impairment that might be linked to functional alterations extending over frontal networks.
authors.affiliation: Center for Psychiatric Neuroscience, Department of Psychiatry, Prilly. Delphine.Preissmann@unil.ch
authors.forename: Delphine
authors.initials: D
authors.lastname: Preissmann
authors.forename: Geneviève
authors.initials: G
authors.lastname: Leuba
authors.forename: Christine
authors.initials: C
authors.lastname: Savary
authors.forename: André
authors.initials: A
authors.lastname: Vernay
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kraftsik
authors.forename: Irène Monika
authors.initials: IM
authors.lastname: Riederer
authors.forename: Françoise
authors.initials: F
authors.lastname: Schenk
authors.forename: Béat Michel
authors.initials: BM
authors.lastname: Riederer
authors.forename: Armand
authors.initials: A
authors.lastname: Savioz
mesh_terms: D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003072:Cognition Disorders / Q000378:metabolism* / Q000473:pathology; D000076122:Disks Large Homolog 4 Protein; D005625:Frontal Lobe / Q000378:metabolism* / Q000473:pathology; D006624:Hippocampus / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D018782:Maze Learning / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism*; D008568:Memory / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D016708:Synaptophysin; C569016:Syp protein, rat; C033652:postsynaptic density proteins