Behavioural and Neuroendocrine Consequences of Prenatal Stress in Rat

Chronic hyperactivation of the hypothalamus–pituitary axis is associated with the suppression of reproductive, growth, thyroid and immune functions that may lead to various pathological states. Although many individuals experiencing stressful events do not develop pathologies, stress seems to be a provoking factor in those individuals with particular vulnerability, determined by genetic factors or earlier experience. Exposure of the developing brain to severe and/or prolonged stress may result in hyperactivity of the stress system, defective glucocorticoid negative feedback, altered cognition, novelty seeking, increased vulnerability to addictive behaviours and mood-related disorders. Therefore, stress-related events that occur in the perinatal period can permanently change brain and behaviour of the developing individual. Prenatal restraint stress (PRS) in rats is a well-documented model of early stress known to induce long-lasting neurobiological and behavioural alterations including impaired feedback mechanisms of the HPA axis, disruption of circadian rhythms and altered neuroplasticity. Together with the HPA axis the glutamate system is particularly impaired, and such impairment appears to be involved in the anxious profile of PRS rats.