Fig. 7.

The HPA axis including the overrepresented neurotransmitter pathways in ME/CFS identified by this analysis. The pathways identified from the overrepresentation analysis and shown here are known to stimulate the HPA axis either directly through the paraventricular nucleus (PVN) with corticotropin releasing hormone (CRH)-producing cells or by an unknown mechanism linked to it. The activation of the CRH sensitive neuronal cells then triggers a downstream stimulation of the anterior pituitary causing the release of adrenocorticotropic hormone (ACTH). ACTH stimulates the adrenal cortex releasing glucocorticoids including cortisol into the body. Cortisol then has a role in the stimulation of a large number of downstream systems involved in a stress response