Category: peptide
Aliases: Vasoactive Intestinal Peptide
Produced in CNS + enteric nervous system; co-transmitter with ACh in PNS. Member of the secretin/glucagon/PACAP family. Activates VPAC1 + VPAC2 (Gs-coupled GPCRs) → cAMP. Effects: vasodilation, smooth-muscle relaxation, water/electrolyte secretion in gut, bronchodilation, T-helper-2 immune shift. VIPoma (pancreatic tumour) causes Verner-Morrison syndrome: watery-diarrhea, hypokalemia, achlorhydria.