Vasoactive intestinal peptide

The vasoactive intestinal peptide (VIP) is a gastrointestinal peptide hormone consisting of 28 amino acids. VIP is formed in the duodenum and has structural similarities to glucagon and secretin. VIP is encoded by a gene located at gene locus Chr 10: 4.7 - 4.71 Mb. Its half-life in blood is about two minutes.

VIP acts as a neurotransmitter and neuromodulator in the neurons of the central nervous system and in parasympathetic nerve fibres. It causes a relaxation of the smooth muscles of the stomach, intestines, trachea and bronchia as well as the blood vessels. VIP acts as a systemic (Greenberg B et al. 1987) and pulmonary arterial (Eriksson LS et al. 1989) vasodilator. Its vasodilating effect is estimated to be 50 times stronger than that of prostacyclin.

VIP acts mainly developed its action via the receptors VPAC1 and VPAC2. The dilatation of the pulmonary blood vessels is mainly caused by an increase in the intracellular cAMP concentration (Cox C P et al. 1984). A stimulating G protein is activated via the VPAC receptors. This G protein activates adenylate cyclase, which in turn produces cAMP. The resulting increased intracellular cAMP concentration leads to relaxation of the smooth muscle cell and thus to vascular dilatation.

VIP also has antiproliferative and possibly antithrombotic properties (Said S 2008). The neurotrophic effects of VIP are also important. It regulates cell growth and neuronal differentiation processes.

Determination of VIP: 1 ml EDTA plasma, freeze immediately; reference range depending on laboratory: up to 71.0 pg/m.

Determination of VIP on suspicion of:

VIPom (Verner-Morrison-Syndrome): Permanent, aqueous diarrhoea with stool quantities > 1 L to 10 L and accompanying hypokalemia, often also achlorhydria (WDHA-Syndrome.

Neuroblastoma and ganglioneuroma, pheochromocytoma with parts of VIP dissecting cells

1. Cox C P et al (1984) VIP Elevates Platelet Cyclic AMP (cAMP) Levels and Inhibits In Vitro Platelet Activation Induced by Platelet - Activating Factor (PAF). Peptides 5: 325-328
2. Eriksson LS et al (1989) Influence of vasoactive intestinal polypeptides (VIP) on splanchnic and central hemodynamics in healthy subjects. Peptides 10: 481-484
3. Greenberg B et al (1987) Relaxant effects of vasoactive intestinal peptides and peptides histidine isoleucine in human and bovine pulmonary arteries. Blood Vessels 24: 45-50
4. Said SI (1988) Vasoactive intestinal peptides in the lung. Annals New York Academy of Sciences 527: 450-464
5. Said S (2008) The Vasoactive Intestinal Peptide Gene Is a Key Modulator of Pulmonary Vascular Remodelling and Inflammation. Ann N.Y. Acad Sci 1144: 148-153