Adrenalectomy and corticosterone replacement differentially alter CA3 dendritic morphology and new cell survival in the adult rat hippocampus

• Published in: Journal of chemical neuroanatomy 2013-03, Vol.48-49, p.23-28
• Main Authors: Martínez-Claros, M., Steinbusch, H.W.M., van Selm, A., van den Hove, D.L.A., Prickaerts, J., Pawluski, J.L.
• Format: Article
• Language: English
• Subjects: Adrenalectomy; Animals; Antimetabolites; Bromodeoxyuridine; CA3 Region, Hippocampal - cytology; CA3 Region, Hippocampal - drug effects; CA3 Region, Hippocampal - ultrastructure; Cell Survival - drug effects; Corticosterone - pharmacology; Dendrites - drug effects; Dendrites - ultrastructure; Dentate gyrus; Dentate Gyrus - cytology; Dentate Gyrus - drug effects; Drug Implants; Hippocampus - cytology; Hormone Replacement Therapy; HPA; Immunohistochemistry; Male; Neurogenesis; Plasticity; Pyramidal Cells - drug effects; Rats; Rats, Wistar; Stress
• ISSN: 0891-0618; 1873-6300
• DOI: 10.1016/j.jchemneu.2013.01.001

► Adrenalectomy results in significant atrophy of CA3 pyramidal neurons. ► Moderately elevated corticosterone replacement result in more new surviving cells in the dentate gyrus. ► Adrenalectomy did not significantly affect survival of new cells in the dentate gyrus. ► Moderately elevated corticosterone replacement had no effect on CA3 cell morphology. Plastic changes in the adult mammal hippocampus can be altered by many factors and perhaps the most well-documented is stress. Stress and elevated corticosterone levels have been shown to decrease hippocampal neurogenesis and decrease the complexity of CA3 pyramidal neurons. However, the extent of these changes in relation to low and moderately elevated levels of corticosterone has yet to be fully investigated. Therefore, the aim of the present study was to determine how low to moderately elevated circulating corticosterone levels affect dendritic morphology of CA3 pyramidal cells and hippocampal neurogenesis in adult male rats. To do this, three groups of adult male Wistar rats were used: (1) Sham-operated, (2) Adrenalectomized (ADX), and (3) ADX+corticosterone replacement. Primary results show that adrenalectomy, but not moderately elevated levels of corticosterone replacement, resulted in significant atrophy of CA3 pyramidal neurons. Interestingly, moderate corticosterone replacement resulted in significantly more surviving new cells in the dentate gyrus when compared to sham controls. This work shows that circulating levels of corticosterone differentially affect plasticity in the CA3 region and the dentate gyrus.