Comparison of hypothalamic-pituitary-adrenal responses to maternal deprivation and chronic variable stress in pre-weanling rats

This paradigm evaluated a novel chronic stressor paradigm that could be as effective as 24 hr of maternal deprivation (24-MD), yet be intrinsically capable of examination over numerous days in pre-weanling pups. It was hypothesized that a 19 hr chronic variable stressor paradigm (19-CVS) would be equally or more effective in eliciting a corticosterone (CORT) response than 24-MD and that 19-CVS would have elevated recovery CORT levels over 24-MD. The results indicated that (1) 19-CVS elicited a significantly greater CORT response than 24-MD immediately after stressor exposure and (2) 19-CVS had significantly elevated recovery CORT in comparison to 24-MD. These results demonstrate that 19-CVS early in development is capable of robustly activating the hypothalamic-pituitary-adrenal (HPA)-axis immediately after exposure and may prove useful as an early life stressor. However, additional work is necessary to clarify how these two distinct stressors differ in termination of their respective HPA response.