Expansion of mossy fibers and CA3 apical dendritic length accompanies the fall in dendritic spine density after gonadectomy in male, but not female, rats.
Androgen loss is an important clinical concern because of its cognitive and behavioral effects. Changes in androgen levels are also suspected to contribute to neurological disease. However, the available data on the effects of androgen deprivation in areas of the brain that are central to cognition, like the hippocampus, are mixed. In this study, morphological analysis of pyramidal cells was used to investigate if structural changes could potentially contribute to the mixed cognitive effects that have been observed after androgen loss in males. Male Sprague-Dawley rats were orchidectomized or sham-operated. Two months later, their brains were Golgi-impregnated for morphological analysis. Morphological endpoints were studied in areas CA3 and CA1, with comparisons to females either intact or 2 months after ovariectomy. CA3 pyramidal neurons of orchidectomized rats exhibited marked increases in apical dendritic arborization. There were increases in mossy fiber afferent density in area CA3, as well as robust enhancements to dendritic structure in area CA3 of orchidectomized males, but not in CA1. Remarkably, apical dendritic length of CA3 pyramidal cells increased, while spine density declined. By contrast, in females overall dendritic structure was minimally affected by ovariectomy, while dendritic spine density was greatly reduced. Sex differences and subfield-specific effects of gonadal hormone deprivation on the hippocampal circuitry may help explain the different behavioral effects reported in males and females after gonadectomy, or other conditions associated with declining gonadal hormone secretion.
Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada.
Ari L
AL
Mendell
Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada.
Sarah
S
Atwi
Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada.
Craig D C
CD
Bailey
Nathan Kline Institute for Psychiatric Research, Center of Dementia Research, Orangeburg, NY, 10962, USA.|Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, 10016, USA.|Department of Physiology and Neuroscience, New York University Langone Medical Center, New York, NY, 10016, USA.|Department of Psychiatry, New York University Langone Medical Center, New York, NY, 10016, USA.|Department of Psychology, College of Staten Island, City University of New York, New York, 10314, USA.
Dan
D
McCloskey
Nathan Kline Institute for Psychiatric Research, Center of Dementia Research, Orangeburg, NY, 10962, USA.|Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, 10016, USA.|Department of Physiology and Neuroscience, New York University Langone Medical Center, New York, NY, 10016, USA.|Department of Psychiatry, New York University Langone Medical Center, New York, NY, 10016, USA.
Helen E
HE
Scharfman
Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada. nmaclusk@uoguelph.ca.
Neil J
NJ
MacLusky
D000728:Androgens / Q000502:physiology*; D000818:Animals; D056654:CA3 Region, Hippocampal / Q000166:cytology* / Q000502:physiology*; D049229:Dendritic Spines / Q000502:physiology*; D005260:Female; D008297:Male; D019599:Mossy Fibers, Hippocampal / Q000502:physiology*; D009919:Orchiectomy; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012727:Sex Characteristics
D000728:Androgens
Androgen; Dendritic spines; Gonadectomy; Hippocampus; Mossy fibers; Sex differences