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Hippocampal damage associated with prolonged glucocorticoid exposure in primates
R M Sapolsky1, H Uno, C S Rebert
1Department of Biological Sciences, Stanford University, California 94305.
Summary
Glucocorticoids (GCs) damage the primate hippocampus. Direct cortisol exposure in vervet monkeys caused significant hippocampal neuropathology, suggesting GCs harm the human hippocampus.
Area of Science:
- Neuroscience
- Endocrinology
- Pathology
Background:
- Glucocorticoids (GCs) damage the rodent hippocampus.
- The effect of GCs on the primate hippocampus remains unclear.
- Previous studies showed stress-induced hippocampal damage in primates, but GC's role was undetermined.
Purpose of the Study:
- To investigate whether glucocorticoids (GCs) cause hippocampal damage in primates.
- To determine if direct cortisol exposure leads to neuropathology in the primate hippocampus.
Main Methods:
- Cortisol pellets were stereotaxically implanted into one hippocampus of 4 vervet monkeys.
- Cholesterol pellets were implanted into the contralateral hippocampus as a control.
- Hippocampal tissues were examined postmortem after one year for neuropathologic markers.
Main Results:
- Cortisol-implanted hippocampi showed preferential neuropathologic damage.
- Damage included cell layer irregularity, dendritic atrophy, and cell shrinkage.
- Damage was severe in some cases, localized to the CA3/CA2 cellfield, mirroring rodent and stress-induced findings.
Conclusions:
- Sustained exposure to glucocorticoids (GCs) causes hippocampal damage in primates.
- This suggests GCs, from stress, Cushing's syndrome, or medication, may harm the human hippocampus.