CRH and major depressive disorder: CRH activates glial-cells and mast cells through CRH receptors and releases neuroinflammatory mediators (42) Mast cells, resident to the brain, are linked to a broad range of neurodegenerative diseases and neuronal disorders such as depression, migraines and autism, likely play a part in the neuro-inflammatory process, and influence “blood-brain-barrier” permeability.