ADCYAP1 and neurodegenerative disease: Interestingly, the VIP pathway inhibits the apoptosis of activated T cells through two neuropeptides VIP and PACAP (pituitary adenylate cyclase-activating polypeptide); these two neuropeptides are key regulators of the function of microglial cells during myelin degeneration and have been associated with a number of neurodegenerative diseases [34].