PACAP consists of 27 or 38 aa residues and belongs to
the secretin/glucagon superfamily. PACAP has pleiotropic
functions, acting as a neurotransmitter and neurotrophic factor in the central nervous system as well as a vasodilator,
insulin secretagogue, smooth muscle relaxant, and immunosuppressor in peripheral tissues. PACAP was first isolated in 1989 from the extract of
ovine hypothalamus on the basis of its ability to elevate
cAMP levels in rat anterior pituitary cells.
