However, at least a research group has succeeded in developing a novel cyclopeptide from the cyclization of PACAP (1–5) that possesses potent activity towards PAC1 and is able to attenuate experimentally-induced diabetes and ganglionic cell death [82, 83], suggesting that advances have been made to overcome the problems associated with poor peptide availability. Here, ADCYAP1R1 is linked to diabetes mellitus.