Brain-corticosteroid hormone dialogue: Slow and persistent

Abstract

1. The stress response system is shaped by genetic factors and life experiences, of which the effect of a neonatal life event is among the most persistent. Here we report studies focused on the "nature-nurture" question using rat lines genetically selected for extreme differences in dopamine phenotype as well as rats exposed as infants to the traumatic experience of maternal deprivation. 2. As key to the endocrine and behavioural adaptations occurring in these two animal models the hormone corticosterone (CORT) is considered. The stress hormone exerts slow and persistent genomic control over neuronal activity underlying the stress response system via high affinity mineralocorticoid (MR) and glucocorticoid receptors (GR). This action is exerted in a coordinate manner and involves after stress due to the rising CORT levels progressive activation of both receptor types. 3. Short periods of maternal separation (neonatal handling) trigger subsequently enhanced maternal care and sensory stimulation. However, a prolonged period (24 h) of depriving the infant of maternal care disrupts the stress hyporesponsive period (SHRP) and causes an inappropriate rise in CORT. During development exposure to CORT and to sensory stimulation has longlasting consequences for organization of the stress response system. 4. We find that these factors embodied by mother-pup interaction are critical for dopamine phenotype, CORT receptor dynamics and neuroendocrine regulation in adult life. The findings provide a conceptual framework to study dopamine-related psychopathology against a background of genetic predisposition, early life events, stress hormones and brain development.

Preliminary associations between childhood neglect, MIF, and cortisol: Potential pathways to long‐term disease risk

“…The HPA axis, a component of the neuroendocrine system, reflects a complex system of direct influences and feedback interactions necessary for adapting to acute and immediate stress. This system also supports the maintenance of circadian rhythms, homeostasis, and metabolic and immune functioning (de Kloet et al, 1996). Persistent activation of this system can promote long-term pathogenesis associated with disease risk (Miller et al, 2009) and is therefore hypothesized to mediate associations between harsh early rearing experiences and long-term mental and physical health problems.…”

Early Life Trauma and Attachment: Immediate and Enduring Effects on Neurobehavioral and Stress Axis Development

“…Moreover, repeated exposure to early life stressors, both physical and psychological, induce changes in endocrine (HPA-axis), neurotransmitter (DA, 5-HT), and brain memory systems, including the hippocampus, amygdala, and PFC that persist throughout the life-span (8, 67, 101, 300, 301). Furthermore, the HPA-axis is modulated by limbic and cortical regions such as the amygdala, hippocampus, and the PFC (269, 302), which enable the activation of stress responses by psychosocial stressors (303–307). Importantly, the timing of early life stress may affect brain regions undergoing specific growth spurts during that time (308, 309), so that brain regions rich in GC receptors and characterized by extended PN development, such as the amygdala, hippocampus, and PFC, are particularly susceptible to the long-term effects of stress (71, 92), which affects later-life memory, cognitive, executive, and affective function as well as stress-reactivity in humans (296, 297).…”

Adolescent Stress–Induced Epigenetic Control of Dopaminergic Neurons via Glucocorticoids

“…The development of means to intervene in such disorders, including prophylactic environmental readjustment (7), would be made easier if more were known about the underlying mechanisms and mediators of such interactions. Studies of dopamine responsiveness in conjunction with the effect of stress hormones in genetically selected rats were among the pioneering efforts in this field (8). …”