Poster Sessions

DEV-1

Jun Chen

J. Chen, Y. Liu, G. Aguilera

Early Life Maternal Deprivation Causes Hypersensitivity of Hypothalamic-Pituitary-Adrenal Axis in Responses to Stress

Negative early childhood experiences, which affect adaptive responses to subsequent stressors during life, play an important role in the development of stress-related mood disorders. In addition, major depression is more prevalent in women than in men. Women with the experience of early life stress are vulnerable to develop depression. However, the consequences of early life stress on sensitivity of adult adaptation to stress exposure and the neurobiological mechanisms are unclear. To investigate whether early life stress affects on sensitivity of adult adaptation to stress and whether female pups are vulnerable to early life stress, we exposed female and male pups to maternal deprivation (MD) as an animal model of early childhood stress. Eight-week old of control or MD rats were exposed to restraint stress as a model of adult psychosocial stress. We found that female MD rats showed an increase in adrenal weight, plasma corticosterone level and hypothalamic Corticotrophine-Releasing Factor (CRF) hnRNA expression, but male MD rats had no significant changes. Subsequent exposure to restraint stress, both male and female MD rat showed a significant increase in plasma corticosterone after restraint 30min, and hypothalamic CRF hnRNA after restraint 1h. DNA methylation analysis indicated that MD rats had a low methylation of CpG in cAMP-responsive element (CRE) of CRF promoter. These findings demonstrate that early life stress induced a high sensitivity of adult responses to subsequent stress. Female pups are more vulnerable to early life stress, which caused up-regulation of HPA axis. The hypersensitivity of HAP axis may be due to the low methylation in CRE of CRF promoter.