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Sexually dimorphic aging of dendritic morphology in CA1 of hippocampus
Author(s) -
Markham J.A.,
McKian K.P.,
Stroup T.S.,
Juraska J.M.
Publication year - 2005
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.20034
Subject(s) - dendritic spine , estrous cycle , sexual dimorphism , hippocampal formation , hippocampus , prefrontal cortex , atrophy , neuroscience , physiology , psychology , medicine , endocrinology , biology , cognition
During aging, rats of both sexes experience a decline in performance on hippocampal‐dependent tasks. Investigations into the neuroanatomical correlates of this functional decline have been conducted almost exclusively in male subjects. In the present study, dendritic spine density in stratum radiatum and complexity of the entire apical dendritic tree were quantified using Golgi–Cox‐stained tissue in young (3–5 months) and aged (19–22 months) rats of both sexes. Because both cognitive decline and hippocampal morphology may be influenced by ovarian hormonal state, young adult females were examined during either proestrus or estrus, and aged females were examined in one of two reproductively senescent states: persistent estrus or persistent diestrus. A sex difference in dendritic branching of CA1 pyramidal cells was found among young adults. However, this difference disappeared during aging, due to a reduction in branching with age for males but not for females. Spine density was not influenced by age or sex, nor did ovarian hormone status influence either measure. These results are consistent with our previous findings in the rat medial prefrontal cortex and primary motor cortex and with the human literature, which indicate that age‐related atrophy of cognitive brain regions is more severe for males than females. © 2004 Wiley‐Liss, Inc.