Prenatal dexamethasone selectively decreases calretinin expression in the adult female lateral amygdala

Abstract

Exposure to high levels of glucocorticoids (GCs) during early development results in lasting disturbances in emotional behavior in rodents. Inhibitory GABAergic neurons, classified by their expression of calcium binding proteins (CBPs), also contribute to stress-related behaviors and may be GC sensitive during development. Therefore, in the present study we investigated the effects of prenatal treatment with the glucocorticoid receptor agonist dexamethasone (DEX) on expression of calbindin and calretinin in brain areas critical to emotional regulation (basolateral/lateral amygdala and hippocampal CA1 and CA3 regions). Late gestational treatment with DEX (gestational days 18–22) significantly decreased the density of calretinin immunoreactive cells in the lateral amygdala of adult female offspring with no differences in the basolateral amygdala, hippocampal CA1, or CA3 regions. Moreover, there were no effects of gestational DEX treatment on calretinin expression in males. Calbindin expression in adulthood was unaltered within either amygdala or hippocampal subregion of either sex following prenatal DEX treatment. Together these findings indicate that late gestational DEX treatment causes a targeted reduction of calretinin within the lateral amygdala of females and this may be one mechanism through which developmental glucocorticoid exposure contributes to lasting alterations in emotional behavior.