A glycosylated pleiotropic peptide pituitary adenylate cyclase-activating polypeptide (PACAP) which can both agonize PAC1 receptors, causing neuroprotective effects, and antagonize VPAC receptors, causing anti-inflammation in several models of acute neuronal damage and neurodegenerative diseases, including ALS, PD, migraines, and certain forms of dementia, is described. Also described is a method of relieving symptoms of ALS, PD, migraines, and certain forms of dementia, comprising administering to a subject in need thereof an effective amount of a glycosylated PACAP.