Activity of the Hypothalamo-Hypophyseal-Adrenocortical System in Prenatally Stressed Female Rats in a Model of Post-Traumatic Stress Disorder.

Changes in the activity of the hypothalamo-hypophyseal-adrenocortical system (HHAS) were studied in adult prenatally stressed female rats in an experimental model of post-traumatic stress disorder (PTSD) in which the animals were subjected to combined treatment consisting of restraint for 2 h, swimming for 20 min, and ether stress, with subsequent restress seven days later (the stress-restress paradigm). An increase in the HHAS stress response was seen after combined stress in prenatally stressed females, apparent at the time of restress. Both control and prenatally stressed animals showed increases in the sensitivity of the hormonal axis to negative feedback signals, which supported accelerated inhibition of the HHAS after its activation by stress. Only prenatally stressed females showed a decrease in the basal corticosterone level and persistence of increased HHAS sensitivity to feedback signals one month after stress and restress. Control females were found to form the PTSD-like state after stress-restress mainly via corticotropin-releasing hormone, while vasopressin was involved in this process in prenatally stressed females. [ABSTRACT FROM AUTHOR]