Low CA1 Spine Synapse Density is Further Reduced by Castration in Male Non-human Primates

Csaba Leranth, Janine Prange-Kiel, Karyn M. Frick, Tamas L. Horvath

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


The hippocampus plays a major role in learning and memory and its morphology and function are readily affected by gonadal hormones in female non-human primates. We sought to determine whether the gonads also affect pyramidal cell spine synapse density in the CA1 hippocampal area of male primates. Unbiased electron microscopic stereological calculations were performed to determine the volumetric density of pyramidal cell spine synapses and semiquantitative analyses on the surface density of glial fibrillary acidic protein-containing glia processes and the diameter of pyramidal cell apical dendrites in the CA1 area of intact and orchidectomized (1 month) St Kitts vervet monkeys (Chlorocebus aethiops sabaeus). The volumetric density (number of spine synapse/μm3) of spine synapses was significantly lower (40%) in the gonadectomized animals than in control monkeys; conversely, the density of glia processes was significantly higher (15%) and the diameter of dendritic shafts located in this area was also larger (30%) in the orchidectomized animals than in the controls. Strikingly, when compared to female values, intact male primates had lower spine synapse densities than either intact or ovariectomized females. Since the primate hippocampus is very similar to that of a human's, the present observations suggest that physiological levels of circulating androgen hormones are necessary to support normal spine synapse density in the CA1 stratum radiatum of human male hippocampus.

Original languageEnglish (US)
Pages (from-to)503-510
Number of pages8
JournalCerebral Cortex
Issue number5
StatePublished - May 2004


  • Electron microscopic unbiased stereological calculation
  • Glial fibrillary acidic protein
  • Orchidectomy
  • Pyramidal cell dendrite
  • Sexual differences
  • Vervet monkey

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Cellular and Molecular Neuroscience


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