Fig. 5
From: Circadian rhythms in the blood–brain barrier: impact on neurological disorders and stress responses
Circadian rhythm and stress response system interactions. The circadian central clock regulates the hypothalamic-pituitary-adrenal axis via projections from SCN that are sent into the paraventricular nucleus (PVN) in the hypothalamus. Stress prompts the release of corticotropin-releasing hormone (CRH) from the hypothalamus. CRH then stimulates the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary gland. Stress response factors, such as glucocorticoids, CRH, and arginine vasopressin (AVP) (also known as antidiuretic hormone (ADH) are secreted rhythmically as signaled by the adrenal cortex whose sensitivity to ACTH is under circadian control. Local adrenal clocks also contribute to the rhythmic secretions and utilize BMAL1 to regulate steroidogenesis. Elevated levels of glucocorticoids due to stress can negatively impact the circadian central clock and dysregulate peripheral clocks. Created with BioRender.com