Age-related spatial learning impairment is unrelated to spinophilin immunoreactive spine number and protein levels in rat hippocampus

Michael E. Calhoun, Bonnie R. Fletcher, Stella Yi, Diana C. Zentko, Michela Gallagher, Peter R. Rapp

Research output: Contribution to journalArticlepeer-review

Abstract

Age-related impairments in hippocampus-dependent learning and memory tasks are not associated with a loss of hippocampal neurons, but may be related to alterations in synaptic integrity. Here we used stereological techniques to estimate spine number in hippocampal subfields using immunostaining for the spine-associated protein, spinophilin, as a marker. Quantification of the immunoreactive profiles was performed using the optical disector/fractionator technique. Aging was associated with a modest increase in spine number in the molecular layer of the dentate gyrus and CA1 stratum lacunosum-moleculare. By comparison, spinophilin protein levels in the hippocampus, measured by Western blot analysis, failed to differ as a function of age. Neither the morphological nor the protein level data were correlated with spatial learning ability across individual aged rats. The results extend current evidence on synaptic integrity in the aged brain, indicating that a substantial loss of dendritic spines and spinophilin protein in the hippocampus are unlikely to contribute to age-related impairment in spatial learning.

Original languageEnglish (US)
Pages (from-to)1256-1264
Number of pages9
JournalNeurobiology of aging
Volume29
Issue number8
DOIs
StatePublished - Aug 2008

Keywords

  • Aging
  • Hippocampus
  • Learning
  • Memory
  • Morris water-maze
  • Rat
  • Spinophilin
  • Stereology

ASJC Scopus subject areas

  • Neuroscience(all)
  • Aging
  • Clinical Neurology
  • Developmental Biology
  • Geriatrics and Gerontology

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