Short term effects of glucocorticoids upon hippocampal ultrastructure

This study evaluated hippocampal cytoarchitecture in male Sprague-Dawley (225-250 g) rats treated with corticosterone (CORT) and in unhandled, unstressed rats. CORT-treated animals received 20 mg/kg CORT in sesame oil/day x 3 days; each dose produces levels in the upper physiologic range, similar to those produced by major stressors. Using quantitative electron microscopy, sections from regions Ca3b, Ca1, and dentate gyrus were examined. Surface density and surface area of Golgi and the number of Golgi-stacks increased following CORT-treatment (p less than 0.05, ANOVA). Paralleling these changes surface area of rough endoplasmic reticulum and number of cisternae also increased in neuronal perikarya (p less than 0.001, p less than 0.003 respectively). In contrast, surface densities of mitochondria, multivesicular bodies, and lysosomes were unaffected by CORT treatment. These data suggest that both pyramidal and granule cells of hippocampus are subject to short term effects of high physiological levels of CORT, and that these effects may involve stimulation of protein biosynthesis.