How do stress hormones affect gene expression and behavior?

Stress hormones can alter gene expression and behaviour through epigenetic modifications.

Stress hormones, such as cortisol, can activate the hypothalamic-pituitary-adrenal (HPA) axis, leading to changes in gene expression. Cortisol binds to glucocorticoid receptors (GRs) in the cytoplasm, which then translocate to the nucleus and bind to specific DNA sequences called glucocorticoid response elements (GREs). This can either increase or decrease gene expression, depending on the target gene and the context of the cell.

In addition to direct effects on gene expression, stress hormones can also induce epigenetic modifications. For example, cortisol can increase DNA methylation, which can lead to long-term changes in gene expression. This can affect behaviour by altering the expression of genes involved in stress response, mood regulation, and cognitive function.

Stress hormones can also affect behaviour through interactions with neurotransmitters. For example, cortisol can reduce serotonin levels, which can lead to symptoms of depression and anxiety. It can also increase dopamine levels, which can enhance reward-seeking behaviour.

Overall, stress hormones can have complex effects on gene expression and behaviour. While acute stress can be adaptive, chronic stress can lead to maladaptive changes in gene expression and behaviour, which can contribute to the development of mental health disorders.